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NOAA Estuary-of-the-Month 
Seminar Series NO. 11 

FEB 1 3 1989 

Tampa and Sarasota" 
Issues, Resources, 



U.S. DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

NOAA Estuarine Programs Office 









^frTtONAt 



NOAA Estuary-of-the-Month 
Seminar Series No. 11 

Tampa and Sarasota Bays 
issues, Resources, 

Status, and Management 


Proceedings of a Seminar 
Held December 10, 1987 
Washington, D.C. 


U.S. DEPARTMENT OF COMMERCE 

C. William Verity, Secretary 

National Oceanic and Atmospheric Administration 

William E. Evans, Under Secretary 


NOAA Estuarine Programs Office 

Virginia K. Tippie, Director 


“ 1 ^ 22-4 

)?n 




b / 


NOAA Estuary-of-the-Month 
Seminar Series No. 11 


TAMPA AND SARASOTA BAYS: 
ISSUES, RESOURCES, STATUS, 
AND MANAGEMENT 


Edited by Ernest D. Estevez 


Proceedings of a Seminar 
Held December 10, 1987 
Washington, D.C. 


U.S. Department of Commerce 
C. William Verity, Secretary 

National Oceanic and Atmospheric Administration 
William E. Evans, Under Secretary 

NOAA Estuarine Programs Office 

Virginia K. Tippie, Director 


i i i 





PREFACE 


The following are the proceedings of a seminar on Tampa and 
Sarasota Bays held on December 10, 1987 at the Herbert C. Hoover Building 
of the U.S. Department of Commerce in Washington, D.C. The Estuarine 
Programs Office (EPO) of the National Oceanic and Atmospheric 
Administration sponsored this seminar as part of a continuing series of 
"Estuary-of-the-Month" Seminars, held with the objective of bringing to 
public attention the important research and management issues of our 
Nation’s estuaries. To this end, participants first presented historical 
and scientific overviews of the bay area, followed by an examination of 
management issues by scientists and resource managers involved in Tampa 
and Sarasota Bays. 

We gratefully acknowledge the assistance of Dr. Ernest D. Estevez 
of the Mote Marine Laboratory, who had principal responsibility for 
assembling the speakers and whose familiarity with the bay area and its 
people was invaluable. Dr. Estevez would like to express his 
appreciation for the dedicated efforts of Linda Franklin, Laurie Fraser, 
Judy Jones, Greg Blanchard, New College Library and the County of 
Sarasota. The seminar was coordinated in Washington by Catherine L. 
Mills, EPO Regional Coordinator, with the help of other members of the 
EPO staff. 

Questions concerning these proceedings may be directed to the NOAA 
Estuarine Programs Office by writing to Room 625 Universal South, 1825 
Connecticut Avenue NW, Washington, D.C. 20235, or by calling (202) 
673-5243. 


v 




TAMPA AND SARASOTA BAYS 
ISSUES, RESOURCES, STATUS, AND MANAGEMENT 


Page 

Preface v 

Table of Contents vii 

List of Speakers and Authors ix 

Introduction xiii 

--Ernest D. Estevez and Kumar Mahadevan 

Geography and Economy of Tampa Bay and Sarasota Bay 1 

--Peter A. Clark and Richard W. MacAulay 

Tampa and Sarasota Bays’ Watersheds and Tributaries 18 

--Michael S. Flannery 

Circulation of Tampa and Sarasota Bays 49 

--Carl R. Goodwin 

Water Quality Trends and Issues, Emphasizing Tampa Bay 65 

--Ernest D. Estevez 

Biology and Eutrophication of Tampa Bay 89 

--Roy R. "Robin" Lewis, III 

Habitat Trends and Fisheries in Tampa and Sarasota Bays 113 

--Kenneth D. Haddad 

Surface Sediments and their Relationship to Water Quality 129 

in Hillsborough Bay, a Highly Impacted Subdivision 
of Tampa Bay. 

--J.0. Roger Johansson and Andrew P. Squires 

Stormwater Impacts to Tampa and Sarasota Bays 144 

--Ronald F. Giovannelli 

Heavy Industry of Tampa and Sarasota Bays 157 

--T. Duane Phillips, Kumar Mahadevan, 

Sandra B. Tippin and Richard D. Garrity 

Ports and Port Impacts 171 

--William J. Tiffany and David E. Wilkinson 

Resource Status and Management Issues of Sarasota Bay 186 

--Ernest D. Estevez and Jack Merriam 

Perspective on Management of Tampa and Sarasota Bays 
--Michael J. Perry 

vi i 


207 


























SPEAKERS AND AUTHORS 


Dr. John V. Betz, Associate Professor, Department of Biology, University 
of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620. (813) 
974-2549. 

Mr. Peter A. Clark, Principal Planner, Tampa Bay Regional Planning 
Council, 9455 Koger Boulevard, St. Petersburg, FL 33702. (813) 577-5151. 

Dr. Ernest E. Estevez, Senior Scientist, Mote Marine Laboratory, 1600 
City Island Park, Sarasota, FL 34236. (813) 388-4441. 

Mr. Michael S. Flannery, Environmental Scientist, IV, Southwest Florida 
Water Management District, 2379 Broad Street, Brooksville, FL 33512. 
(904) 796-7211. 

Dr. Richard D. Garrity, Deputy Assistant Secretary, Florida Department of 
Environmental Regulation, 4520 Oak Fair Boulevard, Tampa, FL 33610. 
(813) 623-5561. 

Mr. Ronald F. Giovannelli, P.E., Principal, Florida Land Design and 
Engineering, One North Dale Mabry Highway, Suite 700, Tampa, FL 33609. 
(813) 875-1115. 

Dr. Carl R. Goodwin, Chief, Environmental Studies Section, U.S. 
Geological Survey, 4710 Eisenhower Boulevard, Suite B-5, Tampa, FL 
33634. (813) 228-2124. 

Ms. Julia E. Greene, Executive Director, Tampa Bay Regional Planning 
Council, 9455 Koger Boulevard, St. Petersburg, FL 33702. (813) 577-5151. 

Mr. Kenneth D. Haddad, Environmental Administrator, Marine Research 
Laboratory, Florida Department of Natural Resources, 100 Eighth Avenue 
SE, St. Petersburg, FL 33702. (813) 896-8626. 

Mr. J.O. Roger Johansson, Chief Biologist, City of Tampa Bay Study Group, 
Department of Sanitary Sewers, 2700 Maritime Boulevard, Tampa, FL 33605. 
(813) 247-3451. 

Mr. Roy R. "Robin" Lewis, III, President, Mangrove Systems, Inc., P.0. 
Box 290197, Tampa, FL 33687. (813) 989-3431. 

Mr. Richard W. MacAulay, Principal Planner, Tampa Bay Regional Planning 
Council, 9455 Koger Boulevard, St. Petersburg, FL 33702. (813) 577-5151. 

Dr. Kumar Mahadevan, Director, Mote Marine Laboratory, 1600 City Island 
Park, Sarasota, FL 34236. (813) 388-4441. 

Mr. Jack Merriam, Director, Natural Resources Management, Sarasota 
County, P.0. Box 8, Sarasota, FL 34230. (813) 378-6113. 


IX 



Mr. Michael J. Perry, SWIM Program Manager, Southwest Florida Water 
Management District, 7601 Highway 301 North, Tampa, FL 33610. (813) 

985-7481. 

Mr. T. Duane Phillips, Senior Biologist, 1600 City Island Park, Sarasota, 
FL 34236. (813) 388-4441. 

Dr. William Seaman, Associate Director, Florida Sea Grant College, 
Building 803, University of Florida, Gainesville, FL 32611. (904) 
392-5870. 

Mr. Andrew P. Squires, Biologist II, City of Tampa Bay Study Group, 
Department of Sanitary Sewers, 2700 Maritime Boulevard, Tampa, FL 33605. 
(813) 247-3451. 

Dr. William J. Tiffany, III, Director of Environmental Affairs, Port 
Manatee, Route 1/Tampa Bay, Palmetto, FL 34221. (813) 722-6621. 

Mrs. Sandra B. Tippin, Environmental Specialist, Florida Department of 
Environmental Regulation, 4520 Oak Fair Boulevard, Tampa, FL 33610. 
(813) 623-5561. 

Mr. David E. Wilkinson, Director of Planning and Development, Port 
Manatee, Route 1/Tampa Bay, Palmetto, FL 34221. (813) 722-6621. 


x 



NOAA "Estuary-of-the-Month" Seminar speakers on Tampa and Sarasota Bays, 
December 10, 1987. Seated, from left: J.O. Roger Johansson, Kenneth D. 
Haddad, Julia E. Greene, Ernest D. Estevez, William J. Tiffany, III. 
Standing, from left: Jack Merriam, John V. Betz, Peter A. Clark, 
Ronald F. Giovannelli, T. Duane Phillips, Michael J. Perry, Michael S. 
Flannery, Roy R. "Robin" Lewis, III, Carl R. Goodwin, William Seaman. 


xi 




































































































































INTRODUCTION 


Reviews of existing data and literature have deservedly become 
regular tasks in the development of natural resource management plans. 
In the cases of Tampa and Sarasota Bays, literature reviews and syntheses 
actually preceded the establishment of management programs. The 1982 
Tampa Bay Area Scientific Information Symposium --or Tampa BASIS-- led to 
a series of management task forces and eventually to the Agency on Bay 
Management, administered by the Tampa Bay Regional Planning Council. The 
Agency’s bay plan, "The Future of Tampa Bay" drew heavily on the 
proceedings of Tampa BASIS. More recently, the Southwest Florida Water 
Management District is producing a legislatively mandated plan for Tampa 
Bay, the implementation of which will draw upon a data compilation 
program conducted for the District by the University of South Florida’s 
Department of Marine Science. Likewise, the proceedings of a 1987 
Sarasota Bay Symposium being prepared by Mote Marine Laboratory will 
provide important technical background for the management conference to 
be convened under the National Estuary Program, beginning late in 1988. 

These NOAA "Estuary-of-the-Month" Symposium proceedings shall 
contribute to the progress of resource management in both bays. For the 
first time, the similarities and differences of the two bays are treated 
together, although it is obvious that more is left to learn concerning 
their relationship than is known already. 

These proceedings appear at a time when two other useful 
literature reviews will become available, one for each bay. The U.S. 
Fish and Wildlife Service is publishing an Estuarine Profile on Tampa Bay 
which is current to approximately 1985, and forms a useful link between 
the Tampa BASIS proceedings and this report. Sarasota Bay information 
bridging the Sarasota Bay Symposium and this report appears in the 
Governor’s nomination of the bay to the U.S. Environmental Protection 
Agency, for inclusion in the National Estuary Program. In fact, the 
paper by Estevez and Merriam contained in this report was adapted from 
the NEP document, with consent of the EPA. 

Despite the fact that symposium speakers have worked in the same 
bays for years and interact at conferences, workshops, and in other 
arenas, all participants left the symposium with new insights to the 
bays, their own work, and the work of others. There was general support 
for periodic, technical exchanges which have not occurred as often as 
policy or planning meetings in recent years. The most interesting 
development was agreement on the value of an ecological model for the bay 
area, proposed by Carl Goodwin of the U.S. Geological Survey. An 
ecosystem model would help identify areas where new research is needed, 
make maximum use of existing data, and provide a mechanism to link lines 
of bay-related research which have been isolated along traditional, 
academic lines for too long. In fact, the new water management district 
plan for Tampa Bay provides for development of an ecosystem model during 
the next five years, and allocates more than one-half million dollars for 
that purpose. 


xi i i 


Finally, it seems that efforts to manage coastal resources are 
beginning to catch up to the phenomenal growth of population which has 
caused so much uncontrolled, adverse environmental impact. The pace of 
resource management is bound to quicken even more as programs take effect 
in Tampa and Sarasota Bays, leading us to believe that universities, 
government laboratories, private research centers, and consulting firms 
will have to grow in size and expertise so as to respond effectively to 
public needs for research and planning. 


Ernest D. Estevez 
Kumar Mahadevan 
Mote Marine Laboratory 
Sarasota, Florida 


xiv 


GEOGRAPHY AND ECONOMY OF TAMPA BAY AND SARASOTA BAY 1 


Peter A. Clark and Richard W. MacAuley 
Tampa Bay Regional Planning Council 
St. Petersburg, Florida 


PHYSICAL GEOGRAPHY 


Tampa and Sarasota Bays are located on the west central coast of 
peninsular Florida (Figure 1). Tampa Bay was formed as a drowned river 
valley during the melting of the last major ice age of the Pleistocene 
Epoch. During that same time period, Sarasota and Palma Sola Bays were 
formed as lagoons behind a chain of barrier islands. 

During the Great Ice Age, the rise and fall of sea level created 
six terraces and historic shorelines in the Tampa Bay Region. The 
terraces and shorelines form belts and occur in step-like formation 
typically running parallel to and rising inland from the coastline. 

Tampa Bay is the largest open water estuary in the state of 
Florida. The estuary is roughly a y-shaped system 35 miles in length and 
10 miles wide. The geographic subdivisions of the bay are represented on 
Figure 2. Combining the open water measurements and intertidal wetland 
areas provides the summary of area measurements for Tampa Bay; these are 
reported on Table 1. In addition, shoreline length measurements for 
Tampa Bay are included on Table 2. 


Table 1. Summary of areal measurements for subdivisions of Tampa Bay, 
including emergent wetlands (Lewis and Whitman 1985). 


Subdivision Name 

mi^ 

km ^ 

Acres 

Hectares 

1. Old Tampa Bay 

80.5 

200.7 

51,542.0 

20,067.2 

2. Hillsborough Bay 

40.2 

105.3 

26,119.6 

10,534.3 

3. Middle Tampa Bay 

119.7 

309.9 

76,547.1 

30,990.7 

4. Lower Tampa Bay 

95.2 

246.6 

60,906.5 

24,658.4 

5. Boca Ciega Bay 

35.9 

93.1 

22,985.6 

9,305.9 

6. Terra Ceia Bay 

8.0 

20.6 

5,098.3 

2,064.0 

7. Manatee River 

18.6 

54.6 

11.935.1 

5,462.0 

TOTAL: 

398.1 

1,030.8 

256,164.9 

103,082.5 


Presented in 1987 by Julia E. Greene, Executive Director, TBRPC. 


1 











(.«*• 

* Apopka 


Hillsborough Count 


Old Tampa 
Bay 


pinellas 
County 


hi 11 ||^rou<jlv 


Tampa Bay 


Gulf of Mexico 


Manatee County 


Figure 1. Location of Tampa Bay in the State of Florida. 


2 



















28 * 15 *- 


82 * 45 ' 


82 * 30 * 


28*00 


27 * 30 * 



27 * 45 '- 


82 * 15 * 

28 * 15 * 


28 * 00 * 


27 * 45 ' 


27 * 30 * 


82 * 45 ' 


82 30 ‘ 


82 * 15 “ 


Figure 2. Subdivision of Tampa Bay (Lewis and Whitman, 1985). 


3 

























































Table 2. Shoreline lengths of subdivisions of Tampa Bay (Lewis and 
Whitman 1985). 


Subdivision Name 

mi 

km 

1. Old Tampa Bay 

211.1 

339.8 

2. Hillsborough Bay 

207.0 

128.6 

3. Middle Tampa Bay 

163.3 

262.8 

4. Lower Tampa Bay 

75.6 

121.6 

5. Boca Ciega Bay 

180.5 

290.4 

6. Terra Ceia Bay 

25.9 

41.6 

7. Manatee River 

118.7 

191.0 

TOTAL: 

903.7 

1,454.2 


Sarasota Bay is approximately 17 miles (27.4 km) long and 3 miles 
(4.8 km) wide and is connected to Tampa Bay on the south by Anna Maria 
Sound and Palma Sola Bay. 

Water level fluctuations within the bay systems occur as a 
combination of diurnal and semidiurnal tides. The change in water level 
results from the sun (diurnal) promoting one high and one low tide daily, 
while the moon (semidiurnal) facilitates two approximately equal high and 
low tides per day. The combination of diurnal and semidiurnal conditions 
ordinarily provides a mixture of both the results in two unequal high 
tides and two unequal low tides each day. 

The watershed, or the area in which all rainwater will eventually 
drain into the bay, is depicted in Figure 3 and is approximately 1,800 
square miles (4,623 km) in size (Lewis and Estevez 1988). Approximately 
85 percent of all freshwater flow to the bay consists of the discharges 
of the four rivers (Lewis and Estevez 1988) which include the 
Hillsborough, Alafia, Little Manatee, and the Manatee. Both Tampa Bay 
and Sarasota Bay additionally receive surface water inputs from numerous 
smaller tidal creeks. 

All of these estuarine water bodies have had past physical 
modifications created to: 

o Develop and expand port facilities 
o Improve navigation 

o Provide transportation routes across the water 
o Build waterfront homes 

o Construct power plants 

o Develop recreational areas 

o Provide flood control 


4 










I Tampa Bay Watershed 


Figure 3. The Tampa Bay watershed (TBRPC, 1984). 


5 




















The Tampa Bay estuarine system is criss-crossed and modified by four 
major causeways and an extensive network of dredged canals. Creation of 
the 35 mile shipping channel resulted in 70 million cubic yards of bay 
bottom being moved and deposited as large spoil island or submerged 
disposal areas in the bay (Figure 4). Previous to dredge and fill 
activities the average depth in Tampa Bay was 11 feet. Due to the extent 
of bay development, the average depth has increased by one foot bay-wide 
and the surface area has diminished by 3.6 percent (Goodwin 1987). 


CLIMATE 


The Tampa Bay Region has a subtropical climate that is 
characterized by long, warm, humid summers and warm winters. In general 
terms, the mild subtropical climate of the watershed is a reflection of 
the low-geographical relief, proximity to the Gulf of Mexico and the 
Atlantic Ocean and the watershed’s relatively low latitude (Schomer, Drew 
and Johnson in press). The slight relief allows an uninterrupted 
movement of wind and rain across the terrain. Because of its history of 
mild climatic conditions and abundant sunshine, the area surrounding 
Tampa and Sarasota Bays has become known as the "Florida Suncoast". 

The average bay area temperature is 23°C (73°F), and freezing 
temperatures are experienced only four nights each year on the average. 
Total rainfall averages 53 inches (134.6 cm) per year. More than half 
the rainfall occurs from June through September, primarily from 
thunderstorms. Approximately 60 to 100 thunderstorms occur in an average 
year, over 85 to 90 days (Lewis and Estevez 1988). 

South Florida has experienced more hurricanes and tropical storms 
than any other equal sized area of the United States. From Cedar Key to 
Fort Myers, eleven (11) storms of hurricane intensity have passed inland 
in recorded history (Schomer et al. in press). The bay area is most 
often hit in the latter part of the hurricane season, usually in 
September and October. 

The primary forces associated with the passage of a hurricane are 
wind, storm surge and rain. In Florida, about 75% of all damage related 
to tropical storms is caused by tidal flooding, with the remaining 25% of 
the damage attributed to winds and rainfall (Schomer et al. in press). 


POPULATION AND SOCIAL FEATURES 


Tampa Bay is bordered by the counties of Pinellas, Hillsborough 
and Manatee, while Sarasota Bay is bordered by Manatee and Sarasota 
Counties. In addition, the two estuaries share twenty-two local 
governments along their peripheries (Figure 5); two regional planning 
councils (Tampa Bay and Southwest Florida); and one water management 
district (Southwest Florida). Population estimates from 1890 reveal that 


6 





Figure 4. Areas of Tampa Bay dredged or filled in the past 100 
years for port development (Fehring, 1985). 


7 









































° f X 3 W 



Figure 5. Political boundaries within the Tampa Bay Region 
(TBRPC, 1984). K 1 


8 


POLK COUNTY HARDEN OOUNTy 



























































approximately 17,836 residents inhabited Hillsborough County (including 
what is now Pinellas County) and Manatee County (including what is now 
Sarasota County) (Figure 6). This number increased approximately 500 
percent to 87,923 in 1910 (U.S. Department of Commerce 1913). The 
estimated population of the four counties in 1950 was approximately 
473,000, increasing 260 percent to approximately 1.23 million residents 
in 1970 (Bureau of Economic and Business Research 1988). The 1987 
estimated population of the area was approximately 2.06 million 
residents. Medium projections indicate that the area’s population will 
reach 2.53 million by the year 2000 --an 18.5% increase over the 1987 
figure (BEBR 1988). 

The Tampa Bay region supports its own symphony orchestra, dance 
and drama companies, and public and private art galleries. In addition, 
the region contains many major attractions which include: 

o Busch Gardens 

o Clearwater Marine Science Center 

o Museum of Science and Industry 

o Ringling Museum Complex 
o Ruth Eckerd Hall 
o Salvador Dali Museum 
o Sunken Gardens, and 
o Tampa Bay Performing Arts Center. 

Professional sports in the area include the Tampa Bay Buccaneers 
(football) and the Rowdies (soccer). The Tampa Bay region served as host 
for the Super Bowl in 1984 and will again host Super Bowl XXV in 1991. 

There are numerous educational and research facilities located in 
the Tampa Bay and Sarasota Bay areas. The University of South Florida 
maintains three campuses in the four county area -- Tampa (main campus); 
St. Petersburg (Bayboro); and Sarasota (New College). The Bayboro area 
of St. Petersburg is also the site of the Florida Department of Natural 
Resources’ Bureau of Marine Research, and the Florida Institute of 
Oceanography. The federal Department of Interior, U.S. Geological Survey 
(USGS) maintains a field office in Tampa, and another office is being 
proposed for the Bayboro area of St. Petersburg. Finally, extensive 
research and study are undertaken at the Mote Marine Laboratory, located 
in Sarasota. 


ECONOMICS 


The presence of Tampa and Sarasota Bays on the Florida "Suncoast" 
has historically shaped and continues to influence the economic base of 
the counties and cities surrounding them. Together, the bays provide two 
of the finest natural harbors on the Gulf coast of peninsular Florida. 
Fishing villages along the shores of both bays became active trade 
centers in the early 1800’s, stimulated by thriving agriculture and 
cattle industries (Powell 1973). The expansion of the railroad system 


9 



population in millions 



Figure 6. Recorded and projected population estimates for Hillsborough, 

Pinellas, Manatee and Sarasota Counties (Department of Commerce, 
1913; BEBR, 1988). 


10 



toward the end of the 19th century is perhaps the single, most important 
reason why the city of Tampa transformed from a viable port city to a 
productive metropolis; moreover, the city’s development into a major 
seaport and trading center influenced the growth and development of the 
entire west coast of Florida (Mormino and Pizo 1983). 

Many of the bay-influenced industries historically important to 
the Tampa and Sarasota Bays area remain key components of the local 
economy today. An economic base analysis conducted in 1986 identified 
agriculture, boat building, commercial fishing, construction and port 
activities to be export industries, or those industries which "drive the 
local economy" (TBRPC 1986). There is much evidence that tourism played 
a major role in the local economy during the 1800’s (Pumphrey 1987). 
Since the 1950’s, however, the bays have increased in economic importance 
for a variety of reasons, principal among these being benefits accrued by 
the sanitary and electric service industries, residential waterfront 
property owners, and the recreation service industry. 

Commercial fishing and port or shipping activities are perhaps the 
most noticeable industrial uses of the two estuaries. Although 
commercial fishermen are reporting that both finfish and shellfish have 
become less abundant over the past 20 years, the industry remains 
important to the local economy. In 1984, approximately 2,000 commercial 
fishermen plied their trade in Hillsborough, Manatee, and Pinellas 
Counties, landing a total of 22.1 million pounds of finfish and 
shellfish, with an ex-vessel value of approximately $19.3 million (TBRPC 
1986). Port Tampa and Port Manatee, both located on Tampa Bay, are major 
sources of employment and income for bay area residents. In addition, it 
has been estimated that shippers and consignees that engage in commerce 
on Tampa Bay realize an annual savings in transportation related costs of 
approximately $281 million, i.e., waterborne commerce versus railroad or 
truck commerce (TBRPC 1986). 

Tampa and Sarasota Bays continue to serve as receiving water 
bodies for discharges of treated wastewater from municipal sewage 
treatment plants. This use of the bays provides a cost savings of 
approximately $238 million, when taking into consideration the 
alternative of secondary wastewater treatment and spray irrigation (TBRPC 
1986). In addition, Tampa Bay serves as a source for condenser cooling 
water and a disposal site for waste heat water from five steam electric 
power plants operated by the Florida Power Corporation and the Tampa 
Electric Company (Phillips, Mahadevan and Garrity this report). This 
results in a cost savings of between $40 and $126 million when 
considering the alternatives of constructing a closed-cycle cooling 
system and on-site cooling towers (TBRPC 1986). 

The construction industry continues to be influenced by the 
presence of both bays, as evidenced by the competition to build 
residential subdivisions, condominiums, office buildings and restaurants 
on the limited amount of land which offers a water vista. The value of 
residential waterfront property along Sarasota Bay has been estimated at 
$1.9 billion (Daltry 1988). Although a similar estimate for Tampa Bay is 


11 


not available, a 1986 study (TBRPC) determined that the most valuable 
attribute (or benefit) provided by Tampa Bay to owners of single-family 
waterfront property was the water view. 

Tourism and recreation are major industries along the Florida 
Suncoast, generating millions of dollars each year. Tampa Bay and 
Sarasota Bay are two of the primary attractors of tourists, as well as 
permanent residents, for recreation. One useful indicator of tourism and 
recreational activity is employment, particularly in those industries 
which are sensitive to tourist expenditures. The retail trade and 
services industries, or sectors, are especially influenced by tourism, 
specifically the hotel/motel industry, eating and drinking 
establishments, and recreation services. The economic base study, 
referred to previously, identified these three sectors as being export 
industries and, therefore, key components of the local economy (TBRPC 
1986). Although the economic study focused on tourism related employment 
in Hillsborough, Manatee, and Pinellas Counties only, it is believed that 
the findings reflect the economic base of Sarasota County, as well. 

Another indicator of tourist activity is that of revenues 
generated by a tourist development (or resort) tax, presently levied by 
Hillsborough, Manatee, and Pinellas Counties on hotels, motels, and 
condominiums rented or leased for a term of six months or less. In 1987, 
26 of Florida’s 67 counties levied a resort tax. Hillsborough, Manatee, 
and Pinellas Counties accounted for approximately 13.2% ($9,248,073) of 
the state total of $69,983,047 (Department of Revenue 1988). 

When compared with Florida’s eastern seaboard and other Gulf coast 
states, the Florida Suncoast ranks as one of the leading sites of marine 
recreational activity, exceeding 25 million activity occasions per year 
in 1980 (Department of Natural Resources 1981). Recreational fishing, 
sailing, swimming, and beach activities are some of the recreation- 
related benefits provided by both the Tampa Bay and Sarasota Bay systems. 
Although tourist and recreational benefits are difficult to quantify, 
there have been attempts made to identify the potential magnitude of the 
recreational benefits associated with Tampa Bay and Sarasota Bay. A 1986 
economic impact statement addressing the designation of Sarasota Bay as 
an Outstanding Florida Water (OFW) estimated the total annual economic 
value of recreational fishing in the Sarasota Bay area to be $38,001,471 
(in 1983 dollars) (Dept, of Environmental Regulation 1986). The economic 
value of other types of water-related recreation, including saltwater 
boat ramp use and beach activities, was estimated to be $9,949,223, for a 
total of $47,950,694 (in 1983 dollars). The same methodology was used in 
another study published in 1986, which estimated the total annual 
economic value of recreational fishing and other types of water-related 
recreation for Hillsborough, Manatee, and Pinellas Counties to be 
$220,176,156 (again, in 1983 dollars) (TBRPC 1986). 

There are over 200 public and private marinas located on the 
periphery of Tampa Bay and Sarasota Bay, some of which are included in 
Figure 7. The number of recreational (pleasure) boats registered in 
Hillsborough, Manatee, Pinellas; and Sarasota Counties is also indicative 


12 



Busch Gardens 

Clearwater Marine Science Center 
Museum of Science and Industry 
Ringling Museum Complex 
Ruth Eckerd Hall 
Salvador Dali Museum 
Sunken Gardens 

Tampa Bay Performing Arts Center 


Fiaure 7. Selected marinas and tourism centers located along Tampa Bay and 

Sarasota Bay. 


13 


























of water-related recreational demands. In 1984, the retail sales 
reported for pleasure boats in the Tampa Bay region was approximately 
$184 million (TBRPC 1986). Table 3 illustrates the number of pleasure 
boats registered in FY 1984-85. The four counties accounted for 
approximately 17 percent of the total number of pleasure boats registered 
in Florida. 


Table 3. Pleasure boats registered FY 1984-85 (BEBR 1986). 


Hillsborough 

33,447 

Manatee 

11,657 

Pinel1 as 

34,541 

Sarasota 

14.702 

TOTAL: 

94.347 

Florida: 

554,675 


The Tampa Bay and Sarasota Bay estuarine systems are both directly 
and indirectly vitally important economic assets to the Florida Suncoast. 
When taking into consideration the myriad of uses and attributes of both 
bay systems including commercial fishing, shipping, and port-related 
activities, benefits to the sanitary and electric service industries, 
waterfront property values, and tourism and recreation, their total 
annual value can be placed at approximately $3 billion (Table 4). Strong 
evidence supports both Tampa and Sarasota Bays’ significant contribution 
to the Florida Suncoast’s rapid growth and development over the past 100 
years. With active protection and management, both bays will continue to 
serve as a valuable, natural --as well as economic-- resource. 


14 




Table 4. Direct and indirect economic benefits of Tampa Bay and 
Sarasota Bay (millions of dollars) (TBRPC 1986; Daltry 1988). 


Bay Use Benefit 

Commercial fishing 1 $ 19.3 
Waterborne commerce 1 281.0 
Sanitary services 2 219.3 
Electric services^ 63.3 
Waterfront property 4 1,900.0 
Tourism/recreation^ 461.4 


TOTAL: $2,944.3 


J Tampa Bay only. 

Considers the alternatives of secondary treatment and spray irrigation. 
^Considers the alternatives of a closed-cycle cooling system and "helper" 
cooling towers. 

4 For Manatee and Sarasota Counties located on Sarasota Bay only. 

^Includes economic value of water-related recreational activities and 
tourist development tax revenues. 


I 


15 





LITERATURE CITED 


Bureau of Economic and Business Research. 1988. Population studies, 
January 1988. Univ. of Fla., Gainesville. 

Daltry, W.E. 1988. The economics of Sarasota Bay. In: E.D. Estevez 
(ed.), Proceedings: Sarasota Bay Scientific Information Symposium. 
Univ. of So. Fla. New College, Sarasota, FL. 

Fehring, W.K. 1985. History and development of the Port of Tampa, In: 
S.F. Treat, J.C. Simon, R.R. Lewis, and R.L. Whitman (eds.). 
Proceedings: Tampa Bay Area Scientific Information Symposium. May 1982. 
Univ. of So. Fla., Tampa, FL. 

Florida Department of Natural Resources. 1981. Marine recreational 
activities. Div. of Recreation and Parks, Tallahassee. 

Goodwin, C.R. 1987. Tidal flow, circulation and flushing changes caused 
by dredge and fill in Tampa Bay, Florida. U.S. Geol. Survey Water Supply 
Paper 2282. Denver, CO. 88 pp. 

Lewis, R.R., III and E.D. Estevez. 1988. The ecology of Tampa Bay, 
Florida: An estuarine profile. U.S. Fish & Wildl. Serv. Office of Biol. 
Serv., Washington, DC. In press. 

Lewis, R.R., III and R.L. Whitman, Jr. 1985. A new geographic 
description of the boundaries and subdivisions of Tampa Bay. In: S.F. 
Treat, J.C. Simon, R.R. Lewis, and R.L. Whitman (eds.). Proceedings: 
Tampa Bay Area Scientific Information Symposium. May 1982. Univ. of So. 
Fla., Tampa, FL. pp. 10-18. 

Mormino, G.R. and A.P. Pizo. 1983. The treasure city: Tampa. 
Continental Heritage Press. 

Powell, E.K. 1973. Tampa that was ... a history and chronology through 
1946. Star Publ. Co. 

Pumphrey, D. 1988. A sense of bay community. In: E.D. Estevez (ed.). 
Proceedings: Sarasota Bay Scientific Information Symposium. Univ. of 
So. Fla., New College, Sarasota, FL. 

Schomer, N.S., R.D. Drew and P.G. Johnson. In press. An ecological 
characterization of the Tampa Bay watershed. A report for the National 
Coastal Ecosystems Team. U.S. Fish & Wildl. Serv., Div. of Biol. Serv. 

Tampa Bay Regional Planning Council. 1984. The future of Tampa Bay. A 
report to the Florida Legislature and TBRPC by the Tampa Bay Management 
Study Commission. Tampa Bay Reg. Plan. Council. St. Petersburg, FL. 
259 pp. 


16 



Tampa Bay Regional Planning Council. 1986. Documenting the economic 
importance of Tampa Bay. A report to the Tampa Bay Regional Planning 
Council and Agency on Bay Management. Tampa Bay Regional Planning 
Council. St. Petersburg, FL. 143 pp. 

United States Dept, of Commerce. 1913. Population-1910. Vol. II. Bureau 
of the Census. Washington Government Printing Office. 

Department of Environmental Regulation. 1986. Sarasota Bay and Lemon 
Bay OFW Designation. Economic Impact Statement for the Proposed Revisions 
of Chapter 17-3.041, F.A.C. 


17 


TAMPA AND SARASOTA BAYS: WATERSHEDS AND TRIBUTARIES 

Michael S. Flannery 

Southwest Florida Water Management District 
Brooksville, Florida 


INTRODUCTION 


Unlike many estuaries in the United States, neither Tampa nor 
Sarasota Bay is associated with a large river. All tributaries flowing 
to these bays originate on the Florida peninsula and, consequently, are 
relatively small (Figure 1). For instance, the largest river flowing to 
Tampa Bay, the Hillsborough, is only 55 miles long. Despite their 
limited size, tributaries to Tampa Bay are important influences on that 
bay’s physico-chemical characteristics. For Sarasota Bay, where 
tributaries are more reduced, these relationships are less pronounced. 
For both bays, however, freshwater tributaries and their associated 
brackish zones are important to estuarine structure and perform 
ecological functions integral to bay productivity. Accordingly, resource 
managers and public officials in the region have clearly stated that the 
proper management of these tributaries is essential for developing bay 
management plans. 

In this paper, the status of tributaries to Tampa and Sarasota 
Bays is reviewed. Emphasis is placed on water quality and seasonal 
quantities of flow and how these characteristics are related to land use 
and other human impacts in the watersheds. A brief synopsis of regional 
meteorological conditions affecting runoff is also presented. Certain 
information presented in this chapter was synthesized from other reviews 
concerning Tampa Bay, particularly those by Lewis and Estevez (1988) and 
Drew, Schomer, and Wolfe (in review). For the sake of brevity, 

references are not extensively used here and uncited information is 
either original or contained in one of the above reviews. Many data 
presented here are only estimates, which the reader should consider for 
future use. 


METEOROLOGICAL CONDITIONS 


The delivery of fresh water to Tampa and Sarasota bays from their 
respective watersheds is a product of the meteorological conditions in 
west-central Florida. The distribution of rainfall is the most important 
variable, but the seasonal variation of other factors such as solar 
insolation, temperature, and evapotranspiration also affect runoff to the 
bays. 


West-central Florida experiences a subtropical climate with mild 
winters and long humid summers. The mean annual temperature for the 
Tampa Bay area is 22.3°C (Wooten 1985) with slightly warmer conditions 


18 





Old Tampa Bay 


Boca Ciega Bay 


Sarasota Bay 


Figure 1. 


Location of tributaries 
drainage areas. 


to Tampa 


and Sarasota Bays and major 


19 







occurring near Sarasota Bay to the south. Average monthly temperatures 
range from 16.0°C to 27.8°C for January and August, respectively. Mean 
annual precipitation for the Tampa Bay watershed is approximately 54 
inches (Heath and Conover 1981). Based on data from 1941 to 1970, Palmer 
(1978) determined that yearly rainfall increased concentrically away from 
Tampa with the most rain falling in the eastern portions of Hillsborough 
and Manatee Counties (Figure 2). For the period 1978 to 1985, however, 
Stowers and Tabb (1987) reported a shift from this historical pattern 
with rainfall increasing in Pinellas and northwestern Hillsborough 
Counties and decreasing in the eastern portions of the watershed. The 
authors attributed this to a change in meteorological conditions 
resulting in a shift in summer winds from easterly to southwesterly but 
state that it is not known whether this represents a short-term cycle or 
a long-term displacement. What is clearly known is that the Tampa and 
Sarasota Bay area has recently been experiencing dry conditions, as 
rainfall has been below average most years since 1961. Palmer and Bone 
(1977) indicated that rainfall at 10 of 14 sites in west-central Florida 
during 1961 to 1976 was the lowest of any of 16 year period since 1915. 
More recently, major droughts occurred in west-central Florida during 
1981 and 1985. 



Figure 2. Distribution of average annual rainfall (inches) in the Tampa 
Bay region of west-central Florida, 1941-1970 (after Palmer 
1978). 


20 








Apart from long term trends in yearly precipitation, the most 
important characteristic of rainfall in the region is its pronounced 
seasonal distribution. A distinct wet season occurs from June through 
September during which approximately 60% of the total yearly 
precipitation falls (Figure 3). This summer wet season is the result of 
local sea-breeze/convection circulation patterns in which moist air from 
the Gulf moves inshore with daytime sea breezes and converges with 
convective air currents caused by the rapid heating of the land surface. 
Rainfall produced from this process generally occurs as brief 
thunderstorms (1-2 hrs) accompanied by strong winds. These thunderstorms 
occur most often during late afternoon or early evening hours, the period 
of maximum atmospheric convergence. One characteristic of these summer 
thunderstorms is the high spatial variation in rainfall. Due to the 
location and variable moisture content of different storm clouds, 
rainfall can vary markedly between stations of close proximity, and 
monthly variations of more than 5 inches have occurred in areas situated 
only a few kilometers apart. 


Average Monthly Rainfall 

Tampa & Bradenton Stations 


10-1 






9 - 

Period of Record 





8 - 

Tampa 1901-1986 

Bradenton 1911-1986 





7- 



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| Bradenton Rainfall |J Tampa Rainfall 


Figure 3. Average monthly rainfall for the Tampa and Bradenton stations. 


21 












Rainfall during the wet season is sometimes supplemented by the 
passage of tropical cyclones (tropical storms and hurricanes), which most 
commonly occur from August through October. During the period 1932-1982, 
five tropical storms and eight hurricanes passed within 75 kilometers of 
Tampa Bay (Wooten 1982). Gentry (1974) reported that 5-10 inches of 
rain are usually recorded at any one point during the passage of a 
tropical storm. 

During November through May rainfall is considerably less than in 
the summer wet season. In contrast to the summer’s convective thunder¬ 
storms, rainfall during this five to six month dry season is associated 
with the passage of large frontal air masses over the state. Generally, 
winter cold fronts proceed in a southerly to southeasterly direction and 
create a preceding band of rainfall which extends along a northeast- 
southwest axis. Rainfall events associated with the passage of frontal 
systems are generally of longer duration but much less intensity than 
summer thunderstorms. These cold front rains are most common during 
January to March, creating a brief elevation in dry season rainfall. The 
driest periods of the year are normally November and April or May, as 
these months occur between periods of intense convective and frontal 
activity. 

Solar radiation varies little geographically, with a daily average 
value of 444 langleys. Highest values occur in spring rather than near 
the summer solstice due to increased cloud cover and precipitation 
(Figure 4). Correspondingly, relative humidity is normally lowest in the 
spring. Evapotranspiration varies spatially throughout west central 
Florida; estimates vary from 30 to 48 inches per year. Based on pan 
evaporation data, average yearly evaporation from open water bodies in 
the region is between 48 and 52 inches, which is only slightly less than 
the average annual rainfall. Pan evaporation rates are highest in the 
spring (Figure 4). 



Figure 4. Average monthly ventilated pan evaporation and solar radiation 
in the eastern Tampa Bay watershed (reprinted from Drew et al. 
in review). 


22 



c.f.s 


SEASONAL STREAMFLOW CHARACTERISTICS 


The yearly cycle of freshwater inflow to the bays closely reflects 
the seasonal progression of climatological conditions in the region. 
Average monthly streamflow values for three long term stations on rivers 
flowing to Tampa Bay are illustrated in Figure 5. Streamflow, like 
rainfall, is highest in the late summer with a much smaller peak in 
February and March. Also, pronounced low flow periods occur in April-May 
and November-December. The differences between spring and wet season 
streamflow values, however, are generally greater than differences 
between spring and wet season rainfall. This is partly because 

streamflow is related to preceding conditions; i.e., increases in 
streamflow during September are associated with already high levels from 
August. Some of the differences between spring and late summer 
streamflow levels, however, are due to higher net runoff during the late 
summer caused by saturated soil conditions. 

Average Monthly Streamflow 

900 - 
800 - 
700 - 
600 - 
500 - 
400 - 
300 - 
200 
100 


0 

J FMAMJJASOND 

Manatee [^] Little Manatee H Alafia 

near Bradenton (discontinued) near Wimauma at Lithia 



Figure 5. Average monthly streamflow for three stations on the Manatee, 
Little Manatee and Alafia Rivers. 


23 












Although the trend shown in Figure 5 is typical of the region, 
seasonal flow characteristics of streams in the area vary due to 
differences in factors such as basin size, land cover, depressional 
storage, and groundwater relationships. For instance, artesian springs 
flow into the Hillsborough and Alafia Rivers providing an important 
source of baseflow during the dry season. Of particular importance are 
the many minor tributaries which drain small, very flat basins. Baseflow 
levels in these tributaries are very small, and total yearly flows are 
dominated by brief periods of runoff after storm events. For these small 
tributaries, the relative differences between dry and wet season flows 
are probably greater than the values for the three rivers displayed in 
Figure 5. 


DRAINAGE AREAS 


The lands supplying runoff to Tampa and Sarasota Bays can be 
conceptually divided into ten drainage areas (Figure 1). Four of these 
areas are the respective basins of the area’s major rivers,which are from 
north to south; the Hillsborough, Alafia, Little Manatee and Manatee 
Rivers. These rivers originate from the higher terraces in the eastern 
portion of the Tampa Bay watershed and flow in a westerly or 
southwesterly direction emptying into the bay on its eastern shore. The 
hydrology and water quality of these four rivers is addressed later in 
this paper. 

The remaining six drainage areas are not true hydrologic basins 
but rather are low-lying coastal areas which are drained by small 
streams, canals, stormwater conduits and tidal creeks. Three of these 
coastal areas comprise the entire drainage to Sarasota, Boca Ciega, and 
Old Tampa Bays. The remaining three areas drain to the eastern shore of 
Tampa Bay between the mouths of the four major rivers (Figure 1). 


MINOR TRIBUTARIES 


The Tampa Bay Regional Planning Council (TBRPC) recently completed 
an ecological assessment and classification of the minor tributaries to 
Tampa Bay (TBRPC 1986). Forty four creeks were identified, although 
three of these were upstream forks of previously mentioned creeks and one 
was a man made canal (Figure 6). These tributaries to the bay ranged in 
total length from 0.5 to 17.5 miles. Although they are largely ungauged, 
it was assumed that average flow in most of these creeks was less than 
their respective tidal prism. In a review of the meteorology and 
hydrology of Sarasota Bay, Walton and Gibney (1988) identified six 
tributaries supplying runoff to Sarasota Bay. The largest of these, 
Phillippi Creek, drains 58 square miles and actually empties into the Bay 
near Little Sarasota Bay, just to the south. The remaining tributaries 
to Sarasota Bay are small, the largest draining only 12.7 square miles. 


24 




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Figure 6. location of minor tributaries in the Tampa Bay region assessed by the Tampa Bay Regional 

Planning Council and their ecological classification (adapted from TBRPC 1986). 






















Despite their small size and limited rates of flow, small 
tributaries and tidal creeks are extremely important components of Tampa 
and Sarasota Bays. Collectively, they provide hundreds of miles of low 
salinity habitat which is utilized as nursery areas by a wide variety of 
marine fishes and some important invertebrates. Many of the most valued 
sport and commercially harvested species in the region such as snook, red 
drum, pink shrimp and tarpon utilize tidal creeks during their life 
cycles. Some regional fishery biologists have expressed concern that the 
abundance and ecological condition of tidal creeks may be a dominant 
factor controlling the productivity of the fishery in Tampa Bay. 

The TBRPC (1986) determined a subjective ecological condition for 
each of Tampa Bay’s minor tributaries based upon a review of adjacent 
land use, habitat, and water quality. These creeks were then given a 
classification of either natural, restorable, or stressed. Of the forty 
tidal creeks considered, nine were classified as natural, eleven as 
restorable, and twenty as stressed. Among the major perturbations to 
tidal creeks in the area were: 

o Habitat loss and water quality impacts associated with filling of 
adjacent wetlands; 

o Loss of natural stream alignment and morphometry due to 
channelization and sea walling; 

o Non point source pollutant loadings from urban and agricultural 
runoff; 

o Point source pollutant loading from municipal and industrial 
discharges; 

o Alteration of flow regimes due to stormwater runoff, channel 
rerouting, and impoundment. 

In response to the need to better manage tidal creek resources on 
Tampa Bay, the TBRPC recommended several policies and guidelines to be 
used in developing management or restoration plans for the bay’s tidal 
creeks. Although not listed here, these recommendations pertained to 
stormwater runoff management, waste effluent control and recycling, 
physical and habitat restoration, freshwater inflow protection, water 
quality monitoring, and resource-compatible land use planning. 


MAJOR RIVERS 


The four major rivers flowing to Tampa Bay collectively drain 
about 75 percent of the Bays’s entire watershed. The drainage basins for 
these rivers range in size from 650 square miles for the northernmost 
Hillsborough River to 221 square miles for the Little Manatee River. 
Progressing from north to south, their tidal floodplains become wider and 
they are tidally affected further upstream. Tidal action is present at 
river mile 11 (mouth=0) in the Hillsborough where the river is dammed and 
at mile 10 in the Alafia River, whereas the Little Manatee is tidal at 
mile 15 and the Manatee is tidal at least to mile 19. The northern 


26 



c.f.s 


rivers (Hillsborough, Alafia) are more urbanized than the southern ones, 
which still contain 90% of their watersheds in wetlands, forest, range, 
and farmland. The Little Manatee watershed is the least urbanized of the 
four rivers and it is generally considered to be the river in the best 
ecological condition. 

Average streamflow rates for these four rivers are presented in 
Figure 7, along with flows for four gauged minor tributaries. Average 
streamflow for the four major rivers correspond to their respective 
drainage basin areas with the Hillsborough having the greatest flow 
followed by the Alafia, Manatee, and the Little Manatee Rivers. Lewis 
and Estevez (1988) estimated that these four rivers contribute 
approximately 85 percent of the total flow to the bay, while Hutchinson 
(1983) indicated this value was near 78 percent. The two largest rivers, 
the Hillsborough and the Alafia, empty into Hillsborough Bay, the 
northeastern division of Tampa Bay. It has been estimated that 
Hillsborough Bay receives 63 to 77 percent of the total freshwater inflow 
to Tampa Bay (Goodwin 1987; Lewis and Estevez 1988). 


Tampa Bay Major Tributaries 


Average Yearly Streamflow and Withdrawals 



mi Streamflow L‘ 1 Withdrawals 

After Withdrawals 


Figure 7. Average yearly streamflow and withdrawals from eight 
tributaries to Tampa Bay. 


27 










Not surprisingly, estimates of total freshwater inflow to Tampa 
Bay contain terms which involve a considerable level of uncertainty. For 
instance, streamflow is not measured for most of the minor tributaries to 
the bay and gauging sites on major rivers are upstream of significant 
portions of their respective drainage basins. Linear extrapolation using 
drainage basin areas can be used to estimate flow from ungauged areas, 
but differences in runoff coefficients may differ and thereby introduce 
sources of error. Even in areas where streamflow is measured, 
differences in length of record can introduce bias into estimates of 
average flows. 

Despite these sources of error, estimates of total tributary flow 
to Tampa Bay have been presented by several authors. Dooris and Dooris 
(1985) estimated average total flow from seven gauged streams at 1,792 
cfs. Goodwin (1987) estimated average total flow to the bay from 
tributaries at 1,904 cfs, but this also did not include estimates of flow 
from ungauged streams. Hutchinson (1983) estimated flow from ungauged 
areas to be 344 cfs, giving a total freshwater inflow of 2,229 cfs to the 
bay. In this report, I have re-estimated average inflow to the bay by 
using streamflow data up to 1986 and employing a factor of 81.5 percent 
for total flow contributed by the four major rivers. This factor is the 
average of the percentages indicated by Hutchinson (1983) and Lewis and 
Estevez (1988). Using this formula, my estimate for total tributary flow 
to Tampa Bay is 2,011 cfs. This estimate accounts for withdrawals made 
from the bay’s tributaries, but does not account for any effluents which 
enter these streams downstream of gauging stations. 

Streamflow Reductions 


As shown in Figure 7, withdrawals are taken from the Hillsborough, 
Manatee, Alafia and Little Manatee Rivers. The Hillsborough and Manatee 
Rivers are impounded by instream reservoirs and withdrawals are made for 
municipal water supply. Included in the values for the Manatee River are 
municipal withdrawals from the Braden River, an impounded tributary to 
the Manatee which enters the main river 8 miles from the bay. In 
contrast to these three instream reservoirs, withdrawals from the Little 
Manatee River are diverted to an offstream reservoir and used for power 
plant cooling water. Withdrawals shown for the Alafia River are actually 
taken from artesian springs which flow into the river. 

Using values from 1987, average daily withdrawals from these four 
streams were 93 cfs for the Hillsborough, 50 cfs for the Manatee, 7 cfs 
for the Braden, 8 cfs for the Alafia and 19 cfs from the Little Manatee. 
Collectively, these withdrawals are equivalent to 8.8% of the estimated 
average streamflow to Tampa Bay, suggesting that the impact of these flow 
reductions may be limited when viewed on a net annual basis. The effects 
of these withdrawals, however, can be very important seasonally. Also, 
the refilling of reservoir storage can markedly increase flow reductions 
during recovery after low flow periods. 


28 



Withdrawals and operating schedules for the three instream 
reservoirs have resulted in the significant reduction of dry season flows 
in those rivers and, periodically, the virtual elimination of flows past 
the dams entirely. This is illustrated in Figure 8, where monthly 
withdrawals and discharge from the Hillsborough River reservoir are 
plotted for October 1982 to September 1986. During this period discharge 
from the reservoir averaged 325 cfs, but there were 547 days when daily 
discharges were less than 20 cfs. Outflows from the Manatee and Braden 
Rivers are similarly affected by extended low or zero flow periods. 


Hillsborough River 

Monthly Discharge and Withdrawals from Reservoir (Oct. 1982-Sept. 1986) 



Figure 8. Monthly discharge and withdrawals from the Hillsborough River 
reservoir. 


The impoundment and utilization of these rivers flowing to Tampa 
Bay has certainly impacted the downstream estuarine environments. The 
most conspicuous effect of instream reservoirs is the elimination of 
movement past that point by migratory organisms such as fishes. This is 
particularly detrimental in estuarine areas where the juveniles of many 
marine species migrate upstream to utilize low and moderate salinity 
habitats. The Braden River dam was built in the estuarine zone of that 


29 






river and functions as a salinity barrier. Also, significant flow 
reductions and the inducement of prolonged periods of low or zero flow 
can result in a lack of flushing and exacerbate water quality problems in 
rivers suffering from eutrophication. Thirdly, flow reductions can 
disrupt salinity distributions in the downstream estuary and cause 
salinity changes from dry to wet seasons to be more extreme. The impacts 
of flow reduction in the Hillsborough River may be somewhat lessened by 
the discharge from the Hookers Point Advanced Wastewater Treatment Plant, 
which discharges an average of 51 mgd of tertiary treated effluent near 
the mouth of the river. Any remedial effects of this freshwater source 
are probably spatially variable, particularly in the lower river, but it 
does provide important inflow to Hillsborough Bay in the dry season. 

It should be stated that the Hillsborough, Manatee, and Braden 
River reservoirs were built before there was a great deal of knowledge or 
concern by the public in the region regarding the importance of 
freshwater inflows for the management of estuarine resources. In fact, 
all three reservoirs were constructed before local regulatory agencies 
had rules regarding the withdrawal and use of surface waters. In 1972, 
the Florida Water Resources Act established five Water Management 
Districts who were given the responsibility of regulating the use of 
water resources in their respective regions. When the Southwest Florida 
Water Management District established its rules regarding consumptive use 
in 1975,there was already heavy reliance on these reservoirs for 
municipal water supply. Since the Tampa Bay area is one of the fastest 
growing regions in the country, this reliance has only grown through the 
years. Since the mid-seventies, however, the Southwest Florida Water 
Management District has addressed the issue of freshwater inflow to 
estuaries by sponsoring seminars, workshops, literature reviews and 
several scientific studies. The goal of this involvement has been to 
better evaluate the freshwater inflow needs of regional estuaries so that 
future water resource development can be done in a manner more compatible 
with the management of estuarine resources. 

Instream reservoirs are not the only method of surface water 
storage used for withdrawals in the Tampa Bay area. Just south of the 
Little Manatee River, the Florida Power and Light Corporation operates a 
4,000 acre offstream reservoir which is used for power plant cooling 
water. Water for this reservoir is diverted from the Little Manatee, but 
withdrawals can only be made when the river is over a particular seasonal 
level. Consequently, environmental impacts have been much less than with 
the three impounded streams. Monthly streamflow and withdrawals from the 
Little Manatee during 1979 to 1985 are shown in Figure 9. Pumpage from 
the river generally is highest during mid to late summer, while 
percentage flow reductions are highest during June and July (Table 1). 


30 


Little Manatee River 

Streamflow and Withdrawals 



Figure 9. Monthly streamflow and withdrawals from the Little Manatee 
River. Streamflow is the sum of values from the Wimauma 

gaging station and withdrawals from the river. 


Table 1. Average monthly rates of withdrawals and percentage flow 
reductions for diversions from the Little Manatee River for 
the period April 1977 through September 1986. 


JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

Withdrawals (cfs) 75 8 2 8 14 22 26 15 1 1 4 

Percent of 

flow (%) 5 3 5 4 8 13 14 8 4 1 2 4 

31 


















































FLOOD CONTROL CHANNELS 


Tampa Bay receives freshwater flow from a number of flood control 
channels. These are manmade canals which diverge from natural waterways 
and are primarily used during intermittent high flow periods. Flows in 
these canals are controlled by gates which are operated in response to 
hydrologic conditions. Channel A, which diverts water from Rocky Creek, 
originates in northwest Hillsborough County and drains to Old Tampa Bay. 
The Lake Tarpon Outfall Canal, which was built in Pinellas County 1971, 
drains the Lake Tarpon watershed and also empties into Old Tampa Bay. 
Flows in this canal, which average 34 cfs, are manipulated to facilitate 
water level fluctuations in Lake Tarpon and to provide storage in the 
lake for the summer rainy season. 

By far the largest flood control structure in the region is the 
Tampa Bypass Canal which was constructed between 1974 and 1983. This 19 
mile structure which lies east of Tampa is used to divert high flows from 
the Hillsborough River and prevent flooding in the cities of Tampa and 
Temple Terrace. The canal originates nearer the Hillsborough River 
northeast of Tampa and empties into McKay Bay, an arm of Hillsborough 
Bay, through the channel of the old Palm River. The lower portions of 
the canal receive flow from groundwater seepage and stormwater runoff, 
although very high flows in the canal are restricted to diversions from 
the Hillsborough River. This operating schedule creates hydrographs 
which are characterized by long periods of relatively stable flows 
followed by abrupt discharge peaks during periodic wet periods, such as 
that accompanying Hurricane Elena in 1985 (Figure 10). 


32 



Tampa Bypass Canal 

Monthly Discharge (Oct. 1982 -Sept. 1986) 



Figure 10. Monthly discharge for the Tampa Bypass Canal. 


WATER QUALITY 


A review of water quality in streams flowing to Tampa Bay can be 
quite extensive depending on the detail of the review. Dooris and Dooris 
(1985) in their review of the quantity and quality of surface flows to 
Tampa Bay discussed twelve stations for which water quality sampling had 
been conducted on a regular basis. Other data exist from a number of 
independent studies,but these data generally cover brief time periods and 
are not available from a centralized data base. The review of the Tampa 
Bay watershed by Drew, et al. (in review) identifies and reviews many of 
these miscellaneous sources of data. Much of the information presented 
here was synthesized from the review of Drew, et al. (in review). Since 
the effects of stormwater runoff and industrial or municipal discharges 
are discussed in other chapters of these proceedings, these topics are 
treated only lightly here. 


33 






In general, streams flowing to Tampa and Sarasota Bays are 

characteristic of the Florida coastal plain. They are generally high in 
color, rich in nutrients, often of sluggish flow, and have seasonally 
fluctuating dissolved oxygen levels due to changes in temperature, 
metabolic activity, and the loading of oxidizable materials from the 

watershed. These streams generally transport low sediment loads due to 
low surface relief within the watershed and a lack of fine grained 
materials in surface soils throughout the region. In addition, virtually 
all streams flowing to the bays have been impacted adversely by urban 
development or agriculture with varying effects on their water quality. 

Water quality data for a number of tributaries to Tampa and 
Sarasota bays are listed in Table 2. These tributaries were selected to 
represent a range of sizes, flows, and impacts due to urban or 

agricultural development. Where possible, data from the most downstream 
station above the tidal reach are listed. As indicated in Table 2, 
however, some data are from brackish zones and an influence of the bay on 
water quality is apparent. A geographic approach is used for discussion 
of these data, beginning with the western shore of Tampa Bay and 

proceeding clockwise. 

Pinellas County 

The southern half of the Pinellas County peninsula exhibits low 
surface relief with a maximum elevation of approximately 25 feet. 
Consequently, no streams of considerable size are found in this region 
and drainage is through stormwater drainage systems, bayous, and tidal 
creeks. Tributaries to Boca Ciega Bay west of Tampa Bay have been 
modified to underground storm sewers or open ditches. Similarly, the 
southeastern portion of the peninsula is drained by ditches and storm 
sewers which empty into small tributaries and bayous of lower Tampa Bay. 
Lopez and Giovannelli (1984) monitored three small creeks in the south 
Pinellas region. Water quality data collected during storm events for 
one of these creeks, Booker Creek, are listed in Table 2. Baseflow in 
these south Pinellas creeks was extremely low, ranging from .57 to 1.0 
cfs, and the majority of nutrient loading to the bays occurred during 
periodic storm events. 

Five small streams draining mid Pinellas County flow easterly to 
Old Tampa Bay. Land use in this region is predominantly urban and at 
least 30% of the area is drained by storm sewers. Water quality data for 
these five creeks are limited to portions of Allen and Alligator Creeks 
(Table 2). Both creeks exhibit wide fluctuations in dissolved oxygen 
levels and high concentrations of nutrients, BOD, and coliform bacteria. 

Lake Tarpon and Northwest Hillsborough County 

From the north, Old Tampa Bay receives flow from three drainage 
areas; Brooker Creek/Lake Tarpon Outfall Canal, Double Branch Creek, and 
the area of northwestern Hillsborough County drained by Rocky and 
Sweetwater Creeks. The Brooker Creek/Lake Tarpon drainage basin is one 
of the most unique systems in the region. Until 1969, Lake Tarpon was 


34 




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35 


Table 2. Mean concentrations of selected nutrients for nineteen tributaries to Taitpa and Sarasota Bays. 










hydraulically connected to the brackish Anclote River to the west through 
a sinkhole in its northwestern end and salinities in the lake fluctuated 
widely. In 1969 a dike was built separating the sink from the lake, 

resulting in a rapid drop in salinity and nutrient levels (Bartos, 

Rochow, and Courser 1977). After removal of the sink, Brooker Creek 
became a more dominant factor influencing the lakes limnology. Brooker 
Creek drains 42 square miles which is characterized by wetlands, citrus 
groves, and numerous lakes. The Lake Tarpon drainage basin including 

Brooker Creek is about 11% urban development with the remainder split 

between wetlands and agriculture. Water quality in the lake is 
relatively good with moderately high nutrient levels, but recent blooms 
of blue green algae have caused concern. As previously mentioned in the 
hydrological discussion, outflow from Lake Tarpon is through the Lake 
Tarpon Outfall Canal which runs south and southeast to Old Tampa Bay. 
Assuming that nutrient concentrations in the outfall canal are similar to 
those in the lake, levels of nitrate, ammonia, and phosphorus are low 
compared to other streams in the region (Table 2). 

To the east of Lake Tarpon lies Double Branch Creek which drains a 
small watershed (19 sq. mi.) at the northern end of the bay. Near its 
mouth the creek is in good physical condition with adjacent tidal marshes 
intact, but high nutrient and bacteria concentrations are found during 
the wet season due to upstream urban and pastureland runoff. 

Perturbations to this creek are much less than for the creeks immediately 

to the east, however, and high color values indicate the influence of 

wetlands in this drainage basin. 

Rocky and Sweetwater Creeks drain northwestern Hillsborough County 
including parts of the City of Tampa and both of these basins have 
experienced rapidly increasing urbanization. Both streams are 
channelized near their mouths and are inter-connected upstream by a flood 
control conduit, "Channel G". Another flood control facility, "Channel 
A", diverges off from Rocky Creek 4.4 miles above its mouth and also 

flows to the bay. Salinity barriers were constructed in Rocky Creek and 
Channel A during 1977-78. Water quality in both Rocky and Sweetwater 
Creeks has been seriously affected by stormwater runoff and municipal 
wastewater discharges, resulting in low dissolved oxygen and high levels 
of coliform bacteria and nutrients, particularly nitrogen species (Table 
2 ). 


South from Sweetwater Creek to the tip of the Interbay Peninsula 
lies the City of Tampa and the remaining drainage to Old Tampa Bay. 
Drainage from this urban area is through underground storm sewers and 
ditches to the bay. One of these drainage systems, the Gandy Boulevard 
Drainage Ditch, was monitored by Lopez and Giovanelli (1984), who found 
that total nitrogen and phosphorus were highest in the baseflow sample, 
but that the majority of nutrients, BOD, and lead were contributed to the 
bay during storm events. 


36 


Hillsborough River 


The Hillsborough River, which enters Hillsborough Bay in the 
center of downtown Tampa, comprises the largest and most diverse basin 
draining to Tampa Bay. All totaled, land use in the Hillsborough River 
basin is estimated at 54% agricultural, 14% range, 13% wetlands, and 15% 
urban. 


The drainage basin for the upper Hillsborough River (headwaters to 
Fletcher Avenue) is primarily agricultural, range, or wetlands as the 
small towns of Zephyrhills and Plant City are the only urban centers in 
the basin. At least ten principal tributaries enter the upper river 
including Crystal Springs, which provides baseflow during dry periods. 
Without going into detail, water quality in several of these tributaries 
has been degraded by agricultural runoff and various industrial or 
municipal discharges. The main channel of the upper river, however, is 
in excellent condition, as the floodplain is largely protected under 
public ownership, and no point source discharges occur on its shore. 
Cypress Creek, a major tributary of the Hillsborough, enters the river 
just above the City of Tampa. This creek drains extensive wetlands and 
contributes water to the river that is high in color and relatively low 
in nutrients, BOD, and bacteria. Due to the assimilative capacity of the 
upper river and the influence of Cypress Creek, water quality problems 
observed in various upstream tributaries are largely unapparent 
downstream. Where it flows into the City of Tampa, the Hillsborough 
River has good water quality characterized by high levels of color and 
dissolved organic carbon and relatively low levels of nutrients, 
turbidity, and coliform bacteria (Table 2). 

Once the river reaches Fletcher Avenue it quickly takes on the 
characteristics of an urban river. Seven miles downstream from Fletcher 
Avenue the river is impounded, creating a long, narrow reservoir which is 
surrounded by the cities of Tampa and Temple Terrace. Lands draining to 
this reservoir are approximately 75 percent urban and 25 percent open 
space. Stormwater from this area, however, averages only five percent of 
the net inflow to the reservoir with the remainder supplied by the river 
(Priede-Sedgwick, Inc., 1980). Principal water quality problems in the 
reservoir are high nutrient and metal concentrations, low dissolved 
oxygen in deeper waters, dense growths of water hyacinths and periodic 
blooms of blue green algae. Algal blooms are most common in spring and 
early summer when flows are low, residence time is long, and temperatures 
are increasing (Metcalf and Eddy, Inc., 1983). 

The lower Hillsborough River consists of the 11 mile, tidally- 
affected reach downstream of the dam. The lower river receives 
freshwater inflow from reservoir releases, stormwater runoff, and Sulphur 
Springs, an artesian spring that averages 40.8 cfs discharge. The 
immediate basin for the lower river is approximately 40 square miles in 
size, intensely urban, and primarily drained by storm sewers. Water 
quality in the lower river is controlled by inflow from the reservoir and 
stormwater runoff, but the effects of stormwater vary considerably 
between seasons and among parameters. Coliform bacteria and heavy metals 


37 



in the river show the closest response to urban runoff in either the dry 
or wet seasons. Phosphorus contributions from stormwater are 
comparatively small, averaging six to ten percent of the total load to 
the river with the remainder coming from upstream sources. Stormwater, 
however, is a significant source of suspended solids, BOD, and total 
nitrogen to the lower river, particularly during the dry season when it 
may account for 37 to 40 percent of the seasonal load (see Drew et al. in 
review). 


The lower river periodically experiences problems with low 
dissolved oxygen which result from excessive algal activity, sediment 
oxygen demand, sluggish flows and tidal salinity effects. Low dissolved 
oxygen levels are closely tied to the location of the salt wedge and 
during the dry year of 1981 were particularly low. Freshwater flow 
suppresses tidal and diurnal (algal) effects on dissolved oxygen 
fluctuations and generally increases the rivers DO concentrations, 
particularly at low to moderate flows. Low DO has been found near the 
dam during high flows, however, when oxygen poor bottom waters from the 
reservoir are released through lower control gates. 

Delaney Creek 

South of the Tampa Bypass Canal, Delaney Creek drains 
approximately 16 square miles of land which is experiencing rapid 
urbanization. A number of industrial point sources discharge into 
Delaney Creek resulting in very poor water quality. Extremely high 
concentrations of nitrogen species in the creek (Table 2) are due to 
discharges from Nitram, Inc., a nitrogen fertilizer processing plant. 

Alafia River 


Of the major rivers flowing to Tampa Bay, the Alafia River is 
notable for its poor water quality. The Alafia drains lands which 
overlie rich phosphate-bearing deposits and extensive phosphate mining 
has occurred in the watershed. Although water quality in the Alafia River 
has been affected by agricultural runoff and miscellaneous point source 
discharges, impacts associated with phosphate mining, processing, and 
enrichment have been the overwhelming perturbations. 

Although perturbations to the river still occur, impacts to water 
quality from the phosphate industry are generally not as severe today as 
in past decades. Prior to the mid-1970’s, the discharge of poorly 
treated or untreated effluents from mines and phosphate or chemical 
processing plants caused extreme loadings of phosphorus, fluoride, 
sulfate, ammonia and acids to the river. During this period the Alafia 
was particularly notorious for high concentrations of phosphorus and 
fluoride. For instance, between 1959 and 1966, total phosphorus 
concentrations commonly ranged between 10 and 30 mg/1 in the main stem of 
the river while fluoride concentrations were generally greater than 10 
mg/1 (Hand, Tauxe and Watts 1986). Water quality in the Alafia basin has 
historically been worst in the North Prong of the river due to the 
abundance of phosphate and chemical processing plant discharges. 


38 




Although it has been extensively mined and is also characterized by high 
constituent levels, the South Prong has had significantly better water 
quality than the North Prong. Water quality below the confluence of the 
North and South Prongs has generally been intermediate between these two 
branches. 

Water quality in the Alafia river basin has shown significant 
improvement since the mid-1970’s due to the implementation of pollution 
abatement practices by the phosphate industry in response to federal, 
state, and local regulations. The recycling and better management of 
waste effluents plus an elimination of slime-pond spills have resulted in 
significant reductions in constituents such as total phosphorus, 
orthophosphate, and fluoride. Nutrient levels are still extremely high 
in the river (Table 2), however, and the Alafia is a major source of 
nutrients to Tampa Bay. Data collected during 1979 indicate that since 
the initiation of advanced wastewater treatment at the Hookers Point STP, 
the Alafia has become the predominant source of both total nitrogen and 
phosphorus to Hillsborough Bay (see Garrity, McCann and Murdoch 1985). 

Flowing into the Alafia River fourteen miles above its mouth is 
Lithia Springs, an artesian system that discharges groundwater at an 
average rate of 46 cubic feet per second. Water quality in the spring 
reflects groundwater conditions, with excellent water clarity and a 
nearly constant temperature year round (75°F). An interesting aspect of 
the spring’s water chemistry is its high nitrate concentrations, which 
ranged from 2.3 to 3.2 mg/1 during 1984-1986. Crystal Springs, which 
flows into the Hillsborough River, similarly show high nitrate levels, 
averaging 1.8 mg/1 during this same period. These data indicate that at 
some locations in Hillsborough County high nitrate groundwaters may have 
a pronounced influence on instream concentrations. Stream-groundwater 
relationships in the region are complex, however, and it is difficult to 
assess how widespread this phenomenon might be. Similarly, the causes of 
high nitrate concentrations in these two springs are not known, and the 
regional extent of this condition is poorly documented. 

Little Manatee River 


The Little Manatee River is the smallest of the four major rivers 
draining to Tampa Bay and is generally considered to be the one in the 
best ecological condition. Land use in the basin is primarily 
agricultural with light urban development occurring on two small 
tributaries and at the town of Ruskin near the mouth of the river. The 
floodplain of the river in the middle and upper reaches is largely intact 
and mangroves or saltmarsh line the shore of much of the lower river. 

Water quality in the upper reaches is generally high in color with 
moderately high nutrient levels, presumably due to agricultural, highway 
and wetland runoff. One phosphate mine, which is currently inactive, has 
a permitted discharge into the headwaters of the river. Nutrient inputs 
from undisturbed soils and vegetative associations are uncertain, 
however, so the effects of land alteration on background nutrient levels 
are difficult to assess. Values for selected water quality parameters 


39 



for a station 15 miles above the river mouth are presented in Table 2. 
This station is about four miles upstream of the maximum penetration of 
brackish water during the dry season and represents the majority of 
inflow to the lower river and Tampa Bay from the watershed. Water 
quality at this station is similar to the upstream reaches, except for 
nitrate concentrations which are markedly greater downstream. The most 
common water quality problem in the Little Manatee River is periodic high 
counts of coliform bacteria. Low fecal coliform to fecal streptococcus 
ratios indicate non human contamination, possibly from feedlots, dairies, 
or fish farms (see Drew et al. in review). 

Although nutrient levels in this river are somewhat elevated and 
significant withdrawals are taken from the river by a local power plant, 
the Little Manatee probably best represents the natural ecological 
interactions of a river and its watershed with Tampa Bay. For that 
reason, the Little Manatee River will be the subject of investigation for 
the next two years in a study supported by NOAA’s coastal grants program 
locally administered by the Florida Department of Environmental 
Regulation. This study will examine runoff (streamflow) quantity and 
quality at several sub-basins within the watershed and compare these to 
land use, soils, vegetation and topography in each sub-basin. In the 
estuary the response of fish, zooplankton, phytoplankton, salinity, water 
chemistry and limiting nutrient conditions will be related to seasonal 
changes in freshwater inflow. It is hoped that this study will enable 
local planners and resource managers to better evaluate the impacts of 
human activities in a watershed to its receiving estuary and, therefore, 
approach the goals of estuarine management from a basin-wide perspective. 

Manatee River 


The drainage basin for the Manatee River is primarily in range 
(41%) and agricultural (38%) land uses. The lower portion of the river, 
however, is heavily urbanized as it flows between the adjacent cities of 
Palmetto and Bradenton. The river is impounded for municipal water 
supply 24 miles above its mouth. Water quality in the upper river above 
the reservoir is generally good, but periodic high levels of phosphorus, 
ammonia and coliform bacteria, however, indicate that agricultural runoff 
is a significant nutrient source. Water quality data from the Manatee 
River reservoir serves as the most downstream station above the lower 
river. Based on the limited data presented in Table 2, reservoir water 
is higher in nitrogen species and organic color than that of the upper 
river. 


Below the dam, Gamble Creek and the Braden River are the major 
tributaries to the river. Gamble Creek experiences high concentrations 
of nutrients and coliforms after heavy rains apparently due to 
pastureland runoff. The Braden River is the largest tributary to the 
Manatee, and its basin is largely in agriculture -- mainly range, 
improved pasture, and cropland. The Braden enters the Manatee 8 miles 
above its mouth, and similarly is impounded for municipal water supply. 
Downstream of the dam the Braden River is estuarine, with salinities 


40 



ranging from 14 to 26 ppt in the dry season to 0 to 19 ppt in the wet 
season (E.D. Estevez, pers. comm.). 

Virtually all of the Manatee River below its reservoir is tidal 1y 
affected and brackish water (>1,000 umhos) comes within three miles of 
the dam during the dry season. The zone of maximum mixing of fresh and 
salt water occurs from 9 to more than 18 river miles above the bay 
depending on seasonal flow. The river below the dam is characterized by 
moderately high nutrient levels, periodic algal blooms and seasonal 
problems with low dissolved oxygen. A study of this portion of the river 
by Manatee County and Camp, Dresser, and McKee, Inc. (1984) examined 
water quality in four ecological zones of the lower river. The zone 
nearest the mouth had the lowest concentrations of nutrients, 
chlorophyll, and coliform bacteria due to the flushing action of lower 
Tampa Bay, a region of the bay with good water quality. In the nine mile 
zone nearest the reservoir, average nutrient concentrations were 
moderately high, but maximum recorded levels of TKN (8.0 mg/1), ammonia 
(.33 mg/1), pH (9.1) and chlorophyll (60 ug/1) were very high, indicating 
occasionally poor water quality conditions. Instantaneous dissolved 
oxygen concentrations in this zone were periodically below state water 
quality standards (4.0 mg/1). 

Another area of the lower river that has periodic water quality 
problems is from the mouth of the Braden River downstream to the main 
bridge between the towns of Palmetto and Bradenton. The City of 
Bradenton’s wastewater treatment plant and a citrus processing plant 
discharge into this portion of the river, and these effluents may be also 
transported up the Braden River on flooding tides. Violations of state 
water quality standards were most numerous in this portion of the river 
with violations for dissolved oxygen concentrations being most common. 
Mean nutrient concentrations were moderately high (Table 2), but maximum 
concentrations of TKN (5.99 mg/1), ammonia (.54 mg/1), chlorophyll (182 
ug/1), and pH (9.37) were very high indicating periodic water quality 
problems. In general, water quality in the lower Manatee River is 
appreciably degraded and suffers from the effects of point source 
discharges, agricultural and urban runoff, and seasonally important 
streamflow reductions. 

Sarasota Bay 

To various degrees, all tributaries to Sarasota Bay have been 
channelized or otherwise modified to facilitate stormwater drainage. 
Water quality data are available for three of these tributaries including 
the two largest drainage systems, Whitaker Bayou and Phillippi Creek. 
Nutrient concentrations are very high near the mouth of Whitaker Bayou 
due to discharges from the City of Sarasota’s wastewater treatment plant 
(Table 2). The plant discharged an average of 8.3 mgd of secondarily 
treated effluent during 1987, but all discharge to the bayou is scheduled 
to be discontinued in late 1988. Phillippi Creek, which is highly 
channelized, similarly receives domestic wastewater discharges in 
addition to stormwater runoff. Nutrient concentrations, particularly 
those for nitrogen species, are high for the station listed in Table 2, 


41 



but greater concentrations are found upstream closer to point source 
discharges. 


WATER QUALITY SUMMARY 


Tampa Bay Tributaries 

Overall, tributaries to Tampa Bay contain high levels of 

nutrients. Mean total phosphorus values for the tributaries listed in 
Table 2 ranged from .30 to .77 mg/1, with the exception of the Alafia 
River and Delaney Creek which had mean values of 2.4 and 2.7 mg/1. For 
the remaining tributaries, phosphorus values were highest for those 

systems which have been impacted by urban runoff or point source 

discharges. Although affected by varying degrees of pollution, three 
river stations --Hillsborough at Fowler Avenue, Little Manatee, and upper 
Manatee-- probably represent the three least impacted sites listed in 
Table 2. Mean total phosphorus concentrations for these three stations 
ranged from .29 to .38 mg/1. 

The concentration of nitrogen species in tributaries to Tampa Bay 
is particularly important because evidence indicates that algal 

production in the bay is primarily nitrogen limited. With the exception 
of Delaney Creek, mean ammonia concentrations in Table 2 ranged from .05 
to .40 mg/1, with the highest values reported from tributaries receiving 
point source discharges (Rocky, Sweetwater) or large quantities of'urban 
runoff. As with total phosphorus, mean nitrate concentrations for the 
Alafia River (1.23 mg/1) and Delaney Creek (9.7 mg/1) were exceptionally 
high compared to other stations, which ranged from .06 to .63mg/l. 

Organic nitrogen values listed in Table 2 ranged from .34 to 2.1 
mg/1, with the highest values reported from Delaney Creek and two of the 
small urban creeks studied by Lopez and Giovannelli (1984). Mean organic 
nitrogen concentrations for the remaining non-tidal stations were less 
than 1.0 mg/1. Total nitrogen values were similarly highest for two of 
the urban creeks and Delaney Creek, but were also high for the Alafia 
River. With the exception of Delaney Creek and the Alafia and Little 
Manatee Rivers, organic nitrogen comprised the majority of mean total 
nitrogen, ranging from 56 to 87 percent. For Delaney Creek and the 
Alafia River, total nitrogen concentrations were strongly influenced by 
high nitrate concentrations, and organic nitrogen averaged 16 and 26 
percent of total nitrogen, respectively. 

Nutrient Loading Estimates 

Nutrient loading estimates can be calculated for tributaries where 
streamflow and water quality data are available. These estimates are 
valuable for they quantify nutrient loading to various portions of the 
bay and provide a measure against which to assess the impacts from 
stormwater runoff or point source discharges. However, due to the 
inadequacies of limited available data, nutrient loading estimates are 


42 





rough approximations and the degree of possible error varies greatly 
between streams. Acknowledging a certain level of uncertainty, nutrient 
loading estimates for eight tributaries to Tampa Bay were made by Dooris 
and Dooris (1985), and large differences in nutrient loading between 
streams were found. Using more recent water quality data, I have re- 
estimated average annual loading of selected nutrients to Tampa Bay for 
the tributaries examined by Dooris and Dooris with the exception of 
Sweetwater Creek. These nutrient loading estimates were calculated from 
the long term average streamflow averages depicted in Figure 7 and the 
mean nutrient values for 1984-85 listed in Table 2. 

These estimates generally supported the tributary ranking by 
nutrient load presented by Dooris and Dooris, but there were some notable 
differences in the results, in particular: greater organic nitrogen and 
nitrate loadings for the Hillsborough and Little Manatee Rivers and Rocky 
Creek; reduced nitrate loading for the Manatee River; and reduced 
phosphorus loading for the Alafia, Hillsborough, Manatee, and Little 
Manatee Rivers. However, in many cases these two analyses used different 
water quality stations and methods for computing total stream discharge; 
therefore, some differences in the results are expected. Due to 
differing methodologies, these two studies cannot be compared to identify 
trends over time, which would require more in-depth analysis of each 
tributary. 

It is also emphasized that these recent estimates, and many of 
those presented by Dooris and Dooris, are biased for nutrient loading 
above the brackish portion of each river and nutrient additions to the 
lower reaches of the rivers are largely ignored. For some tributaries 
(e.g., Manatee River and Rocky Creek), these downstream nutrient 
additions are particularly high, and reported nutrient loads seriously 
underestimate final nutrient loading to the bay. Since most of the 
localized nutrient loading to these lower tributary reaches is from 
stormwater runoff or point source discharges, a separate analysis of 
those factors may account for their effects. 

The seven tributaries for which nutrient loading estimates are 
made are listed in Table 3 by their average ranking based on loadings of 
total phosphorus and total nitrogen. The Alafia River has the highest 
estimated loading rates for these two parameters and nitrate. This was 
particularly pronounced for total phosphorus, as the estimated annual 
load for the Alafia was more than five times greater than the value for 
the next highest river. Similarly, the phosphorus load for the Alafia 
was 71% of the total load for the seven listed tributaries. 

The four major rivers were more closely grouped for estimated 
total nitrogen loads, with values ranging from 2.7x10^ kg/yr for the 
Little Manatee to 8.6x10^ kg/yr for the Alafia. Loading estimates for 
organic nitrogen were even more closely grouped, ranging from 1.2xl0 5 
kg/yr to 3.2x10^ kg/yr, with the Hillsborough and Manatee Rivers having 
the highest values. The results for nitrate loadings were similar to 
total phosphorus in that the Alafia had markedly higher values than the 
other tributaries due to its high nitrate concentrations. 


43 


LOADING (Kg/Year) 


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44 


Table 3. Estimated average annual loading of selected nutrients for seven tributaries to Tampa Bay. Numbers in 
parentheses refer to water quality stations in Table 2 used for computation. For tributaries denoted by 
an asterisk (*), results should be viewed with caution, as they do not account for substantial downstream 
nutrient additions. 




In total, the seven tributaries listed in Table 3 are estimated to 
contribute an average of 1.95x10 5 kg/yr total nitrogen and 1.35x10^ kg/yr 
total phosphorus to Tampa Bay, reiterating that this does not account for 
substantial nutrient additions to the lower reaches of certain rivers. 
These summed nutrient loading values gives a nitrogen/phosphorus ratio of 
1.6, indicating that tributary inflow to the bay is very phosphorus 
enriched. Much of this is due to the enormous phosphorus load of the 
Alafia River. The ratio of summed nitrogen and phosphorus loadings for 
the other six tributaries is 3.3, which still indicates freshwater rich 
in phosphorus. Fanning and Bell (1985) similarly reported that Tampa Bay 
is considerably enriched in phosphorus, but stated that causes for this 
may be complex, involving leaching of phosphate beds, agricultural 
runoff, point source discharges, etc. 


CONCLUSIONS 


An evaluation of tributary nutrient loading and its effect on bay 
water quality is one of the most important aspects of bay management. 
This chapter has reviewed the streamflow and water quality 
characteristics of tributaries to Tampa and Sarasota Bays but has not 
specifically considered their relationships to bay water quality. That 
topic is discussed in the review of water quality presented later in 
these proceedings. Instead, the emphasis here is that tributaries to 
Tampa and Sarasota Bays must also be managed for their own values, i.e., 
the tidal creek and river habitats upstream of their mouths. 
Collectively, tributaries to these bays include hundreds of miles of low 
and moderate salinity habitats. These tidal habitats are normally 
heavily vegetated by intertidal marshes or mangrove swamps, and are 
important nursing grounds for many of the bays’ most valuable fishery 
species. If these areas are to maintain their biological function, 
various physical and chemical perturbations, such as channel and 
shoreline alterations, freshwater inflow disruptions and nutrient loading 
from point and non-point sources, must be controlled. The Surface Water 
Improvement and Management Act passed by the Florida Legislature 
specifies that Tampa Bay and its tributaries are priorities for 
conservation, management, or restoration. The assessment of Tampa Bay’s 
tidal creeks recently published by the Tampa Bay Regional Planning 
Council (1986) suggested guidelines for improved tributary management. 
Other state and local agencies have sponsored water quality or ecological 
studies on tributaries in the region. With the current level of 
knowledge and commitment, the management of tributaries to Tampa and 
Sarasota Bays should be much improved over previous years. With continued 
population growth, however, management efforts must be persistent if 
environmental qualities are to be preserved or in some cases restored. 


45 



LITERATURE CITED 


Bartos, L.F., T.F. Rochow and W.D. Courser. 1977. Third Annual Progress 
Report - 1975 - monitoring of Lake Tarpon fluctuation schedule. 

Southwest Florida Water Management District. Brooksville, FL. 

Dooris, P.M., and G.M. Dooris. 1985. Surface Flows to Tampa Bay: 
Quantity and Quality Aspects. Pp. 88 to 106 In: S.F. Treat, J.L. Simon, 

R. R. Lewis, III, and R.L. Whitman, Jr. (eds.), Proceedings, Tampa Bay 
Area Scientific Information Symposium. Burgess Publishing Co., Inc., 
Minneapolis, MN. Available from Tampa Basis, P.0. Box 15759, Tampa FL. 

Drew, R.D., N.S. Schomer, and S.H. Wolfe. In review. An Ecological 
Characterization of the Tampa Bay Watershed. U.S. Department of the 
Interior Fish and Wildlife Service. Biol. Rept. 87(xx). Washington, DC 
20240. 

Fanning, K.A. and L.M. Bell. 1985. Nutrients in Tampa Bay. Pp. 109- 
129, S.F. Treat, J.L. Simon, R.R. Lewis, III, and R.L. Whitman, Jr. 
(eds.), Proceedings, Tampa Bay Area Scientific Information Symposium. 
Burgess Publishing Co., Inc., Minneapolis, MN. Available from Tampa 
Basis, P.0. Box 15759, Tampa FL. 

Garrity, R.D., N. McCann, and J. Murdoch. 1985. A Review of the 

Environmental Impacts of Municipal Services in Tampa. Pp. 526-550 In: 

S. F. Treat, J.L. Simon, R.R. Lewis, III, and R.L. Whitman, Jr. (eds.), 
Proceedings, Tampa Bay Area Scientific Information Symposium. Burgess 
Publishing Co., Inc., Minneapolis, MN. Available from Tampa Basis, P.0. 
Box 15759, Tampa, FL. 

Gentry, R.C. 1974. Hurricanes in South Florida. Pp. 73 81 In: P.J. 
Gleason, (ed.), Environments of South Florida: Present and Past. Miami 
Geol. Soc. Mem. 2. 

Goodwin, C.R., 1987. Tidal-Flow, Circulation, and Flushing Changes 

Caused by Dredge and Fill in Tampa Bay, Florida. U.S. Geol. Surv. Water 

Supply Paper; 2282. 

Hand, J., V. Tauxe and J. Watts. 1986. Alafia River Basin Technical 
Report. Water Quality Monitoring Technical Report No. 44. Florida 

Department of Environmental Regulation, Tallahassee, FL. 

Heath, R.C. and C.S. Conover. 1981. Hydrologic Almanac of Florida. 
U.S. Geol. Surv., Open File Report 81-1107, Tallahassee, FL. 

Hillsborough County Environmental Protection Commission. 1986. Water 
Quality 1984-1985: Hillsborough County, Florida. Tampa, FL. 

Hutchinson, C.B. 1983. Assessment of the Interconnection between Tampa 
Bay and the Floridan Aquifer, Florida. U.S. Geol. Surv. Water Resources 
Investigation, 82-54,Tal1ahassee, FL. 


46 



Lewis, R.R., III, and E.D. Estevez. 1988. The Ecology of Tampa Bay, 
Florida: An Estuarine Profile. U.S. Department of the Interior Fish and 
Wildlife Service, Washington, DC. 

Lopez, M.A. and R.F. Giovanelli. 1984. Water-quality characteristics of 
urban runoff and estimates of annual loads in the Tampa Bay area, 
Florida, 1975-1980. U.S. Geological Survey Water Resources 
Investigations Rept. 83-4181. Tallahassee, FL. 

Manatee County Utilities Department and Camp, Dresser and McKee, Inc. 
1984. Downstream Effects of Permitted and Proposed Withdrawals from Lake 
Manatee Reservoir. Report submitted to the Southwest Florida Water 
Management District, Brooksville, FL. 

Metcalf and Eddy, Inc. 1980. Tampa Nationwide Urban Runoff Program. 
Phase I. Task 1.3.D-Receiving Water Study and Task 1.6A-0verall 
Assessment. Department of Public Works, City of Tampa, FL. 

Palmer, C.E. 1978. Appendix C - Climate In: Water Management Plan 78. 
Southwest Florida Water Management District, Brooksville, FL. 

Palmer, C.E. and L.P. Bone. 1977. Some Aspects of Rainfall Deficits in 
West-Central Florida: 1961-1976. Hydrometeorological Rep. No. 13. 
Southwest Florida Water Management District, Brooksville, FL. 

Priede-Sedgwick, Inc. 1980. Tampa Nationwide Urban Runoff Program, 
Phase 1. Task 1.3B and Task 1.3C. Report submitted to the Department of 
Public Works, City of Tampa, FL. 

Sarasota County Division of Environmental Services. 1985. Ambient Water 
Quality, Sarasota County, Florida. Sarasota, FL. 

Sarasota County Division of Environmental Services. 1986. Ambient Water 
Quality, Sarasota County, Florida. Sarasota, FL. 

Stowers, D.M. and N.D. Tabb. 1987. An investigation of the variances 
from the traditional summer precipitation in the west-central Florida 
region (1978-1985). Fla. Scientist 50(3):177-183. 

Tampa Bay Regional Planning Council. 1986. Ecological Assessment, 
Classification and Management of Tampa Bay Tidal Creeks. Tampa Bay 
Regional Planning Council, St. Petersburg, FL. 

United Stated Geological Survey. 1986a. Water Resources Data, 1984: 
Volume 3A. Southwest Florida Surface Water. U.S. Geol. Surv. Water-Data 
Report FL-85-3A, Tallahassee, FL. 

United States Geological Survey. 1986b. Water Resources Data, 1985: 
Volume 3A. Southwest Florida Surface Water. U.S. Geol. Surv. Water-Data 
Report FL-86-3A, Tallahassee, FL. 


47 


Walton, R.W. and R.A. Gibney. 1988. Meteorology and Hydrology of 
Sarasota Bay. In: E.D. Estevez (ed.), Proceedings, Sarasota Bay Area 
Scientific Information Symposium (in press). 

Wooten, G.R. 1985. Meteorology of Tampa Bay. In: S.F. Treat, J.L. 
Simon, R.R. Lewis, III, and R.L. Whitman, Jr. (eds.), Proceedings, Tampa 
Bay Area Scientific Information Symposium. Burgess Publishing Co., 
Minneapolis, MN. Available from Tampa Basis, P.0. Box 15759, Tampa, FL. 


48 


CIRCULATION OF TAMPA AND SARASOTA BAYS 


Carl R. Goodwin 
U.S. Geological Survey 
Tampa, Florida 


INTRODUCTION 


Before addressing the subject of circulation in Tampa and Sarasota 
Bays, it is appropriate to place these two coastal water bodies in 
physical perspective with another well-known estuarine system, San 
Francisco Bay. Figure 1 shows the plan view of each of these three bay 
systems to the same scale and also gives the names of major sub- 
embayments or defined sub-units. For purposes of this article, San 
Francisco Bay is defined to include South, Central, San Pablo, and Suisun 
Bays. Tampa Bay includes Lower, Middle, Old Tampa, and Hillsborough 
Bays. Table 1 lists several physical attributes of each bay system. San 
Francisco Bay is the largest in every category, with Sarasota Bay often 
at least one order of magnitude smaller. Tampa Bay has about 25% less 
surface area than San Francisco Bay. It is also more shallow and has 
less than half the tidal range. San Francisco Bay receives more than 12 
times the average freshwater inflow of Tampa Bay and 1,000 times that of 
Sarasota Bay. 


Table 1. Physical attributes of Sarasota, Tampa, and San Francisco Bay. 


Physical Attribute 

Sarasota 

Bay 

Tampa 

Bay 

San Francisco 
Bay 

Surface area (sq. mi.) 

54 

347 

440 

Average depth (ft) 

5 

12 

19 

Tidal range (ft) 

1.3 

2 

5 

Volume (sq. mi-ft) 

270 

4,140 

8,440 

Tidal prism (sq. mi-ft) 

70 

760 

2,010 

Average annual inflow volume 
(sq. mi-ft) 

27 

2,150 

26,500 


49 





122° 30' I22°00' 



o O o 

co r- 

cm cvj oj 


U) 

<D 

£ 



-to 


-o 


o - 1 



50 


Figure 1. Size compaxison of Saxasota Bay and the San Fxancisco Bay and Tampa Bay systems. 









DISCUSSION 


The two physical attributes giving the most insight into the type 
of circulation that exists in each system are the tidal prism (the volume 
of water added to the bay between low slack and high slack tides at the 
bay mouth) and average annual freshwater inflow volume. These attributes 
are convenient measures that are often used to represent tidal (mixing) 
and freshwater (stratification) influences, respectively. In situations 
where freshwater inflow dominates, conditions are favorable for formation 
of significant vertical density stratification with denser salty water on 
the bottom and less dense fresher water on the top. In conditions where 
tidal effects predominate, fresh and salt waters are well-mixed with 
little vertical variation of density. This distinction is important 
because the type of circulation likely to be found in an estuary is 
closely linked to its degree of stratification. 

Harleman and Abraham (1966) combined tidal prism and average 
freshwater inflow into an "estuary number" that can be used as a general 
index of the degree of stratification in bays and estuaries. Using this 
technique, an estuary number of 100 is a dividing point with values 
greater than 100 indicating increasingly well-mixed conditions and values 
less than 100 indicating increasingly stratified conditions. The 
stratification numbers for Sarasota, Tampa, and San Francisco Bays are 
about 1,000, 200, and 30, respectively. 

For well-mixed conditions --such as those found in Tampa and 
Sarasota Bays-- tidally averaged horizontal circulation patterns 
predominate (Figure 2). These patterns are caused by the interaction of 
tidal water motion with the bottom configuration and general shape of the 
estuary. For stratified conditions --such as in San Francisco Bay-- 
horizontal patterns can still exist, with the added complication of a 
vertical circulation (Figure 2). The vertical pattern is caused by the 
tendency for freshwater to override the denser saltwater. 

Little is known about the overall circulation pattern in Sarasota 
Bay. A few glimpses are available from the literature, however, that 
indicate existence of interesting circulation patterns. Fortune (1985, 
written communication) has reported on the paths of a series of drogues 
released in Sarasota Bay for a period of about 36 hours. Several drogues 
grounded in close proximity and others showed large net motion between 
tidal cycles. As part of a numerical modeling study of hurricane surge 
heights, Ross, Anderson, and Jerkins (1976) reported a nodal point in the 
central part of the bay. 

In contrast, circulation in Tampa Bay has been the subject of 
several studies, including those by Ross and Anderson (1972), Ghioto 
(1973, written communication). Cote (1973, written communication), Ross 
(1973), and Goodwin (1977, 1980, and 1987). Results from many of these 
studies have shown numerically that tidally averaged water motion in 
Tampa Bay is comprised of a series of horizontal circulation features 
that are thought to control the overall movement and distribution of 


51 



CROSS SECTIONAL VIEW OF VERTICAL 
TIDALLY AVERAGED 
CIRCULATION PATTERN 


V 



PLAN VIEW OF HORIZONTAL TIDALLY 
AVERAGED CIRCULATION PATTERN 



Figure 2. Vertical and horizontal tidally-averaged circulation patterns 
in estuaries. 


52 





















dissolved and suspended material in the bay. The content of this paper 
is largely taken from the results of Goodwin (1987) and Goodwin (in 
press). 


As previously mentioned, horizontal circulation is a tidally 
averaged water motion that is caused by interactions between incoming 
(flood) and outgoing (ebb) tidal flows and bay geometry. Figure 3, 
depicting tidal flood (3a), tidal ebb (3b), and tidal 1y averaged (3c) 
water motion in a region at the mouth of Hillsborough Bay (see Figures 1 
and 7), illustrates this phenomenon. A primary feature of the bay’s 
geometry in this region is an east-west oriented ship channel with two 
dredge-material islands on the south side of the channel. The channel is 
about 25 feet deep, and the surrounding bay depths vary from 5 feet or 
less near the eastern shore to about 15 feet on the western edge of the 
illustrated area. 

Visual comparison of the flood and ebb patterns of flow shows a 
large westward component in and along the ship channel during ebb that is 
not balanced by an equivalent eastward flow during flood. The fact that 
the channel lies to the north of the islands provides a path of little 
resistance to help convey ebb flows westward. No similar pattern forms 
during flood flow because the channel is then in the lee of the islands. 
Through an entire tidal cycle, the overall effect of the channel and 
islands is to produce a tidally averaged net or residual motion that is 
westward along the channel (Figure 3c). Because (in a net sense) the 
westward moving water must be replaced, circulation cells are set up to 
accomplish this and maintain continuity of mass throughout the affected 
region. This rather extreme example of geometry-controlled flow and 
circulation patterns is, nonetheless, a valid description of how 

horizontal circulation features are generated throughout Tampa Bay. This 
type of circulation has been called "tidal pumping" by Fischer, List, 
Imberger, and Brooks (1979). 

Circulation features computed in Tampa Bay, using a simulation 
model having a grid size of 1,500 feet, are shown in Figure 4 for 
conditions as they existed in 1985. The 20 or so annotated circulation 
features indicate the complexity of the overall pattern of bay 

circulation that is believed to play a large role in the distribution and 
flushing of dissolved and suspended material. For comparison and a 
visual indication of the cumulative effects of dredge and fill 
activities, Figure 5 shows computed circulation patterns for 1880 
conditions. Impacts of construction of ship channels, causeways, 
islands, and shoreline fills have been to both intensify and distort 

circulation features that existed prior to construction as well as to add 
new circulation features. 

To compare circulation changes between 1880 and 1985, Goodwin 
(1987) plotted a measure of circulation intensity as a function of 
distance (Figure 6) and identified six zones from the Gulf of Mexico to 
the head of Hillsborough Bay having different circulation 
characteristics. Circulation zones are shown in Figures 4 and 5, and 

Table 2 gives the average circulation computed for each zone for 1880 and 


53 




0 3,000 


LENGTH SCALE 
(FEET) 


Figure 3. Flood (3A), ebb (3B), and tidally-averaged (3C) flow patterns 
in a region near the mouth of Hillsborough Bay. 


54 




































28 ' 


82 ° 30 



Figure 4. Tampa Bay tidally-averaged flow pattern in 1985 with computed 
circulation features and circulation zones. 


55 







































































28 


82 ° 30 



27 ° 30 ' 


Figure 5. Tampa Bay tidally-averaged flow pattern in 1880 with computed 
circulation features and circulation zones. 


56 













































































































CIRCULATION, IN THOUSANDS 



DISTANCE FROM WESTERN BOUNDARY OF ZONE 1, IN MILES 


Figure 6. Comparison of computed circulation in Tampa Bay for 1880 and 

1985. 


57 































1985 conditions, as well as the percentage change. In both 1880 and 
1985, computed circulation in zone 3 is less than in either zone 2 or 
zone 4, although not as pronounced as 1985. It is not known whether the 
circulation minimum in zone 3 influences the overall rate of constituent 
flushing from Tampa Bay to the Gulf of Mexico. Circulation differences 
range from a decrease of about 10 percent in zone 1 at the mouth of the 
bay to an increase of 275 percent in Hillsborough Bay (zone 6). The 
large computed increase in Hillsborough Bay circulation was investigated 
in more detail by Goodwin (in press) using a 500-ft grid model having 
nine times more spatial resolution than the Tampa Bay model. This model 
assumes no difference between 1880 and 1985 freshwater inflow. It does, 
however, include a total bay volume increase of about 10 percent and a 
tidal prism decrease of 6 percent during the same period. 


Table 2. Circulation changes in Tampa Bay between 1880 and 1985 by zone. 


Circulation 


Zone 

in cubic 
1880 

feet per second 

1985 

Percent 

Change 

1 

45,500 

41,100 

- 9.7 

2 

10,400 

13,400 

+28.8 

3 

4,900 

6,300 

+28.6 

4 

8,600 

7,800 

- 9.3 

5 

2,700 

3,700 

+37.0 

6 

400 

1,500 

+275.0 


The smaller grid model confirmed that dredge and fill construction 
of channels, islands, and shoreline fills between 1880 (Figure 7a) and 
1985 (Figure 7b) caused a dramatic increase in the number and intensity 
of circulation features in Hillsborough Bay (Figure 8). A comparison 
plot of circulation versus distance from the mouth of Hillsborough Bay 
(Figure 9) also demonstrates large circulation increases in most parts of 
the bay between 1880 and 1985. 

In addition to obvious circulation dissimilarities, the 500-foot 
grid model also revealed what is believed to be an important similarity 
in the Hillsborough Bay circulation patterns of 1880 and 1985. There is 
a tendency for tidally averaged water motion to flow in a seaward 
direction along the shallow bay margins and in a landward direction in 
the deeper central part of the bay. Although unconfirmed by direct flow 
measurements, this computed pattern is at least partially substantiated 


58 




27° 55* 


27°50’ 


27 e, 45' 


Figure 


82 ° 30' 82°25‘ 82°30* 82°25‘ 



7. Shorelines of Hillsborough Bay in 1880 (A) and 1985 (B). 


59 













82 ° 30 


82 ° 25 


82 ° 30 


82 ° 25 ‘ 


27° 55* 


2 7° 50 


27°45 




EXPLANATION 


ANNOTATION SHOW 
INO CIRCULATION 
FEATURES 


MOUTH OF 
HILLSBOROUGH 
BAY 


ti r 

0 12 3 

KILOMETERS 


Figure 8. 


Tidally-averaged flow pattern with computed 
features in Hillsborough Bay in 1880 (A) and 1985 


circulation 
(B). 


60 

























































































































































































































CIRCULATION, IN THOUSANDS OF 


O 

O 

UJ 

</> 

CL 

UJ 

a. 

H 

UJ 

UJ 

u. 

o 

so 

3 

o 



DISTANCE FROM MOUTH OF HILLSBOROUGH BAY, IN MILES 

(SEE FIG. 8) 


Figure 9. 


Comparison of computed circulation in Hillsborough Bay for 
1880 and 1985. 


61 






by the 12-year average salinity distribution of Hillsborough Bay 
(Figure 10). 

Assuming that this generalized, tidal 1y averaged flow concept is 
correct, Goodwin (in press) estimated how circulation increases between 
1880 and 1985 may have changed the average time needed for suspensed or 
dissolved material to transit from the head to the mouth of Hillsborough 
Bay. The transit time in 1880 is estimated to have been about 60 days. 
Due to increased circulation, the transit time in 1985 is estimated to 
have been about 30 days. This indicates that Hillsborough Bay may now be 
able to flush itself of waterborne material having a landward source in 
about half the time that it took in 1880. 

It is likely that increased flushing has also caused an increase 
in bay salinity because tributary freshwater inflow to Hillsborough Bay 
can also be conveyed through the bay in about half the time that it took 
in 1880. The salinity increase in the bay from 1880 to 1985 due to 
increased flushing is computed to be in the range of 2 to 3 parts per 
thousand. Reductions in Hillsborough River discharge (Flannery, this 
report) probably have also contributed to an increase in bay salinity, 
but this effect has not been quantified. 

In spite of the circulation information available for the Tampa 
Bay system, much more remains unknown. Questions regarding the effects 
of wind are unanswered for both Tampa and Sarasota Bays. Are wind 
effects dominant or do they represent short-term perturbations on the 
tide-induced circulation? Another unanswered, circulation-related 
question that has a large bearing on overall flushing rates and the 
concentration of waterborne constituents is the mechanism of exchange 
between bay and gulf waters. Of the water exiting Tampa and Sarasota 
Bays during ebb tide, what percentage returns during the next flood tide? 
These and other Tampa Bay questions are addressed in a comprehensive 
management plan, as requested in Florida’s Surface Water Improvement and 
Management Act of 1987. Similar answers are being sought for Sarasota 
Bay through a federally sponsored estuarine initiative administered by 
the U.S. Environmental Protection Agency. 


62 


82 ° 30 ' 82 ° 25 ' 



Figure 10. Distribution of average salinity in Hillsborough Bay computed 
from 12 years of monthly observations. 


63 















LITERATURE CITED 


Fischer, H.B., J.E. List, J. Imberger and H.H. Brooks. 1979. Mixing in 
inland and coastal waters. Academic Press, NY. 483 pp. 

Goodwin, C.R. 1977. Circulation patterns for historical, existing, and 
proposed channel configurations in Hillsborough Bay, Florida, pp. 167- 
179, Proceedings, 24th International Navigation Congress. 

Goodwin, C.R. 1980. Preliminary simulated tidal flow and circulation 
patterns in Hillsborough Bay, Florida. U.S. Geol. Surv. Open File Rept. 

80-1021. 28 pp. 

Goodwin, C.R. 1987. Tidal-flow, circulaton, and flushing changes caused 
by dredge and fill in Tampa Bay, Florida. U.S. Geol. Surv. Water-Supply 
Paper 2282. 88 pp. 

Goodwin, C.R. In press. Tidal-flow, circulation, and flushing changes 
caused by dredge and fill in Hillsborough Bay, Florida. U.S. Geol. Surv. 
Water-Supply Paper. 

Harleman, D.R.F. and G. Araham. 1966. One-dimensional analysis of 
salinity intrusion in the Rotterdam Waterway. Delrt Hyd. Lab., Publ. 
No. 44. 

Ross, B.E. 1973. The hydrology and flushing of the bays, estuaries, and 
nearshore areas of the eastern Gulf of Meixo, In: A summary of knowledge 
of the eastern Gulf of Mexico. St. Petersburg, FL, Fla. Inst, of 
Oceanogr. pp. IID1-IID45. 

Ross, B.E. and M.W. Anderson. 1972. Courtney-Campbell Causeway tidal 
flushing study: Report to the Florida Department of Transportation, Tampa 
Bay Regional Planning Council St. Petersburg, FL. 16 pp. 

Ross, B.E., M.W. Anderson, and J. Jerkins. 1976. Hurricane tide heights 
at Longboat Key. Tampa, Fla. Univ. of So. Fla. College of Engineering. 


64 



WATER QUALITY TRENDS AND ISSUES, EMPHASIZING TAMPA BAY 


Ernest D. Estevez 
Mote Marine Laboratory 
Sarasota, Florida 


INTRODUCTION 


Modern reports of water quality in Tampa Bay go back 150 years, in 
the form of accounts of red tides, fish kills due to freezes, and mass 
mortalities of bay life caused by heavy rains and runoff. Even earlier 
records of water quality may be read in the shell middens created by 
prehistoric humans, by the seasonality of deposits, identity and size of 
shelled animals, or their microscopic or chemical structure. In this 
paper, I shall review a much more recent collection of facts about Tampa 
and Sarasota Bays, actually just more than one decade’s worth, to fulfill 
NOAA’s request that readers might learn (from existing information) 
something about overall water quality in the bays, and ongoing or new 
issues or management programs related thereto. 

The water quality of Tampa and Sarasota Bays is rather well-known 
but poorly understood because the underlying chemistry and biology which 
control water quality have received scant attention. Water quality 
refers to measurable comparisons to specific standards or designated 
uses, and in a more general way includes parameters associated with 
violations or loss of use, although their direct, mechanistic link to an 
impact is unclear. For example, Florida has no specific standard for 
nitrogen and excess nitrogen does not impair human contact or use, j)er 
se, but nitrogen’s known origin in effluent and runoff and role as a 
stimulant of phytoplankton blooms cause it to be monitored as an 
indicator of water quality. 

The statement that local water quality is well known is true in 
the following senses but with certain qualifications. Compared to other 
estuaries of the nation, Tampa Bay’s continuous monitoring program is 
relatively mature (16 years). The program covers the entire bay and 
tributaries, although very shallow areas are probably under-represented. 
Quality control has been above average although a change in analytical 
technique for nitrogen prevents meaningful trend analyses. There is also 
a feeling among bay area scientists and resource managers that the very 
large data base is not being utilized fully to understand processes 
controlling water quality, such as weather, runoff, circulation, and 
biological interactions. 

Nevertheless, the general water quality monitoring program in 
Tampa Bay is a facet of resource management deserving national attention. 
The program was begun in 1972 by the Hillsborough County Environmental 
Protection Commission (HCEPC) and covers all of Tampa Bay, even the 
waters of Pinellas and Manatee Counties (which have not assisted HCEPC 


65 



with monitoring expenses). The program entails monthly sampling at 54 
bay and 12 tidal tributary stations, with in situ measurements and water 
samples taken near the surface, middle, and bottom of the water column. 
Twenty-eight parameters are measured. Results are reported every two 
years in graphic and text form. More than 388,000 data are available for 
trend analysis of parameter-specific and "general" water quality of the 
bay, and another two-year report for 1986-87 is in press. 

Comparison to Other Systems 

In their Tampa BASIS review of nutrients, Fanning and Bell (1985) 
stated, "Compared to other estuaries and coastal waters, Tampa Bay is 
considerably enriched in phosphate. In fact, no other major estuarine 
or coastal area we know of even comes close to having as high a phosphate 
concentration". The Alafia River has been the primary source of 
phosphate because it [and neighboring rivers] drain the lands east of the 
bay which are underlain by a phosphate-rich "Bone Valley" Formation. 
Industrial discharges elevated phosphate levels in the river and bay for 
decades but these levels are declining as water conservation and 
discharge limits are enforced. The same geology and industrial 
processing have caused relatively high levels of radionuclides in the 
upper bay (Fanning, Breland and Byrne 1982). 


GENERAL WATER QUALITY 


Standards and Beneficial Uses 


Waters of Tampa and Sarasota Bays are classified by the State of 
Florida as Class II or III, which provide for shellfish propagation or 
harvesting and maintenance of fish and wildlife, respectively. Both 
categories recognize body contact with bay water as a safe use (Table 1). 
Actual taking of shellfish is limited to smaller parts of Class II waters 
because of contamination from runoff, and sewage treatment plants. 
Despite such contamination, most of the two bays are also classified as 
"Outstanding Florida Waters", which is supposed to prevent degradation of 
existing water quality by applying more stringent conditions on state 
discharge and dredge-fill permits. Except for Sarasota Bay, all 
outstanding waters are also state aquatic preserves. The preserves are 
managed to perpetuate their ecological, recreational, or scenic 
qualities. 

Bav-wide Assessments 

The State of Florida made a recent assessment of Tampa Bay’s water 
quality (Palmer and McClelland 1988) and concluded that "overall water 
quality in Tampa Bay is improving. Furthermore, the long-term averages 
indicate that the water quality throughout the bay is fairly good. 
However, water quality standards violations do occur in all of the major 
bay segments with Hillsborough Bay and Old Tampa Bay generally exhibiting 
the worst problems." Another, earlier assessment by the State of water 


66 







quality throughout Florida (Hand, Tauxe and Watts 1986) determined 
whether Tampa and Sarasota Bays were meeting their designated uses 
(Figure 1). That report identified poor water quality in Hillsborough 
Bay and its tributaries, eutrophication problems caused by STP effluent 
in Old Tampa Bay, and good water quality in the Little Manatee and 
Manatee Rivers, and Lower Tampa Bay. Sarasota Bay was found to have fair 
to good water quality. [Note: the Florida DER is producing a 1988 
biennial report to EPA with more current findings; the 305(b) Report will 
be available late in 1988]. 

Table 1. Water quality classifications and designated uses of Tampa and 
Sarasota Bays. 


Aquatic 



Class 

Preserves 

OFW* 

Shellfish 

Old Tampa Bay 

II 

Pinellas 

West Side 

Closed 

Hillsborough Bay 

III 

None 

None 

Closed 

Tampa Bay 

II, III 

3 Preserves 

3 Preserves 

Mixed 

Boca Ciega Bay 

II 

All 

All 

Closed 

Sarasota Bay 

II, III 

None 

All** 

Mixed 


* Outstanding Florida waters 
** Except creek mouths 


Data from the HCEPC monitoring program have been used for years to 
develop bay-wise water quality assessments (Boler 1986). The HCEPC 
employs a "general water quality index" comprised of dissolved oxygen, 
chlorophyll a, total coliform, biochemical oxygen demand, total 
phosphorus, total Kjeldahl nitrogen,and effective light penetration data. 
A scale is used to generate points for each parameter and points are 
weighted and summed to produce the water quality index. The index is 
computed for each station and values between stations are interpolated 
for graphic presentation. 

General water quality is highest in the lower bay and poorest in 
Hillsborough Bay (Figure 2). Water quality is best in the dry season and 
worst in the wet season (Figure 3). There has been a general improvement 
in water quality throughout the bay since 1975, even when years of 
relatively low rainfall are considered (Figure 4). Improvements in 
Hillsborough Bay are attributed to the City of Tampa’s advanced waste 
treatment plant, and are believed responsible for the colonization of 
shallows along the Interbay Peninsula by seagrasses and rhizophytic 
macroalgae (City of Tampa 1988). 

Overall, Lewis and Estevez (in press) concluded that Tampa Bay is 
not grossly polluted, certainly not beyond the point of rehabilitation; 
that parts of the bay had better water quality than others, for natural 
and cultural reasons; and that some pollutants are declining while others 
are increasing. 


67 









Figure 1. Tampa Bay water quality. Good water meets designated uses; 

use of fair water is partially met. Poor water does not meet 
designated use (Hand et al. 1986). 


68 



















SYMAP 


Figure 2. General water quality index, 1984 (Boler 1986). 


69 














































































1984 GENERAL WATER QUALITY 



SINIOd IOM 


70 


Figure 3. Seasonal variation in water quality in Hillsborough Bay (HB); Lower Tampa Bay (LTB) ; Middle 
Tampa Bay (MTB) and Old Tampa Bay (OTB), from Boler (1986). 





GENERAL WATER QUALITY 1975-1985 

(TOTAL KJELDAHL NITROGEN NOT INCLUDED) 



SINIOd I DM 


71 


Figure 4. Annual trends in general water quality (Boler 1986). 






PARAMETERS OF INTEREST 


Reports by the HCEPC allow the depiction of spatial and temporal 
patterns useful in comprehending the bay’s overall character, and 
relationship to other estuaries. Most of the following discussion is 
adapted from Boler (1986) for 1984 or 1985. Rainfall in 1984 was below 
average (32.3 inches) compared to 1985 (44.6 inches). 

Salinity 

Salinity ranges from nearly zero in tidal rivers to normal 
salinity of the Gulf of Mexico. Salinity less than 50 percent occurs in 
Old Tampa and Hillsborough Bays, and the tidal rivers. Runoff affects 
the upper bays more than the lower bay (Figure 5). The mid-bay area 
usually exhibits the greatest transitional salinities. 

Light 


The color, nutrient-enhanced plankton, and detritus associated 
with runoff reduce light penetration in approximately the same areas and 
times of salinity reduction (Figure 6). Seasonal variation in light 
climate is much more complicated than salinity, however, owing to the 
non-conservative nature of some light-controlling factors. Since 1974, 
mean Secchi depth for Lower Tampa Bay has exceeded 70 inches, where 
seagrasses are most abundant, whereas the middle bay area has had some 
years with less than 70 inches of effective light penetration. Upper bay 
areas have had the poorest light climate, especially Hillsborough Bay 
(Figure 7). 

Chlorophyll 

Chlorophyll a levels between 10.0-15.0 ug/1 are common throughout 
much of Tampa Bay inland of the Sunshine Skyway Bridge, and chlorophyll 
concentrations greater than 20 ug/1 are common in Hillsborough Bay 
(Figure 8). A slight increase in chlorophyll may be occurring through 
time over several bay areas although levels in Hillsborough Bay appear to 
be declining (Figure 9). In developing a water quality model for 
Hillsborough Bay, Ross, Ross and Jerkins (1984) included a self-shading 
factor to account for the inhibition of photosynthesis by very high 
concentrations of phytoplankton in surface waters, as reflected by 
chlorophyll level. 

Nutrients 


The exceptional levels of total phosphorus (TP) in Tampa Bay were 
introduced in an earlier section. In 1984, TP ranged from 1.55 mg/1 as P 
in Hillsborough Bay (at the Alafia River) to 0.08 mg/1 at Egmont Key 
(Figure 10). Phosphorus levels have been declining for more than a 
decade (Figure 11) owing to environmental regulations and production 


72 











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73 














































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74 



























EFFECTIVE LIGHT PENETRATION 1974-85 



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Figure 7. Annual trends in effective light penetration (Boler 1986). 









Figure 8. 


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a, 1984 (Boler 1986). 


76 








































































CHLOROPHYLL A 1974-85 



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77 


Figure 9. Annual trends in d^orophyll a (Boler 1986). 







SYMAP 


Figure 10. 


Mean annual total phosphorus, 1984 (Boler 1986). 


78 
















































































TOTAL PHOSPHOROUS 1974-85 


ro 



1/OkN 


79 


Figure 11. Annual trends in total phosphorus (Boler 1986) 







declines in the Alafia River Basin. Even so, the north prong of the 
Alafia River had an annual average phosphorus concentration of 7.68 mg/1 
in 1984 (Boler 1986). 

Nitrate-nitrite-nitrogen concentrations were relatively low in 
1984, as in most years, with highest levels in Hillsborough Bay. Total 
Kjeldahl nitrogen concentrations were more uniform throughout the bay in 
the same year, with all but gulf stations with geometric means greater 
than 0.5 mg/1. (Ten-year trend analyses for nitrogen are unavailable 
because analytical methods changed in 1980.) 

Dissolved Oxygen 

In 1984 all mean annual bottom concentrations of dissolved oxygen 
were greater than 5.0 mg/1, except for McKay Bay, an arm of Hillsborough 
Bay. In the subsequent, wetter year of 1985, mean annual concentrations 
of dissolved oxygen at the bottom were less than 5.0 mg/1 along the 
western shore of Hillsborough Bay and the shallow waters of middle Tampa 
Bay. In general, bottom dissolved oxygen minima were greater than 
3.5 mg/1 throughout all of Tampa Bay except Hillsborough Bay (Figure 12), 
although conditions in Hillsborough Bay are improving (Figure 13). 
Table 2 summarizes extreme dissolved oxygen conditions in Tampa Bay and 
accentuates Hillsborough Bay as the area of greatest fluctuation. 


Table 1. Frequency {% total samples) of violations (<4.0 mg/1) and 

supersaturation of dissolved oxygen (adapted from Palmer 
and McClelland 1988). 


Area 

N 

% Violations 

% SuDersaturated 

Hillsborough Bay 

surface 

1421 

5 

61 

bottom 

1408 

20 

33 

Old Tampa BayZ 

surface 

1478 

0 

56 

bottom 

1479 

2 

45 

Middle Tampa Bay 

surface 

1126 

0 

66 

bottom 

1123 

3 

39 

Lower Tampa Bay 

surface 

946 

0 

72 

bottom 

945 

0 

59 


80 











SYMAP 


Figure 12. 


Means (based on second minima) of dissolved oxygen at the 
bottom, 1984 (Boler 1986). 


81 









































































DISSOLVED OXYGEN BOTTOM 

AVERAGE OF MONTHLY MINIMUM VALUES 



l/OVI 


82 


Figure 13. Annual trends in bottom dissolved oxygen (Boler 1986). 



WATER QUALITY IS IMPROVING, BUT... 


The State of Florida, local regulatory officials, and bay 
scientists presently believe that water quality of Tampa Bay is 
improving, and that such improvements are the result of active regulation 
and management. There have been tangible improvements since 1974 in many 
key parameters and rooted vegetation is reappearing in shallow waters of 
Hillsborough Bay. How long can these improvements continue; what 
emerging problems could undermine such progress; and what are the natural 
constraints to bay recovery? 


Natural Conditions Affecting Water Quality 

1. Weather 

The bay areas experience one or two days of freezing temperature 
every year or two. Freezes result in fish kills in shallow waters and 
damage mangroves. Heavy leaf drop 1-3 months following freezes results 
in temporarily high detritus and particulate organic levels which are 
probably offset in subsequent years by reduced production in cold-damaged 
forests. Years of above-average rainfall or shorter periods following 
hurricanes result in heavy runoff, causing rivers to freshen throughout 
their length and the bays to have much lower salinity than usual. Heavy 
runoff also increases color and turbidity, and can result in fish kills 
due to salinity shock, periods of reduced oxygen, or both. 

2. Anoxia 

Hillsborough Bay is the only segment of either study area in which 
periods of partial to complete oxygen depletion have been documented. 
Oxygen stress is most severe near the bottom due to benthic respiration, 
phytoplankton self-shading, and the increased light path over channels 
dredged to 42 ft depths. Up to half of Hillsborough Bay’s surface area 
has experienced oxygen stress in particular years, resulting in 
defaunation of benthic invertebrates. Defaunation corresponds to times 
of anoxia, which occur most often in July, August, and September (Santos 
and Simon 1980). The extent to which anoxia in Hillsborough Bay is a 
naturally occurring event is not known, but some anoxic conditions 
probably occurred prior to urbanization due to the combined discharges of 
three rivers in a naturally deep arm of the bay where wind-driven mixing 
is limited. Anoxia occurs in Charlotte Harbor (south of Sarasota Bay) 
due to discharge of the Peace River. Anoxia in the Harbor is considered 
to be a naturally-occurring event because that bay is relatively 
pristine, so part of the oxygen stress in Hillsborough Bay is probably 
natural as wel1. 


83 




3. Sediments 


The bottom of Tampa Bay, especially Hillsborough Bay, exerts a 
substantial influence on water quality. Biota such as clams filter 
particulates from enormous volumes of bay water and seagrasses trap 
suspended sediment, but accumulations of fine, organic sediments play an 
even greater role by acting as sources --and sinks-- of nutrients. 
According to Ross et al. (1984), the benthos stores 84% of the carbon, 
85% of the nitrogen, and 65% of the phosphorus moving through Tampa Bay’s 
ecosystem. Preliminary estimates of flux rates are shown in Figure 14. 
The central role of sediments as a nutrient problem have caused engineers 
to propose either dredging or capping of the benthos. Others counter 
that sediment release of nutrients at high rates mean that benthic 
conditions will improve if given enough time without the heavy loadings 
which have occurred for almost a century. A detailed look at sediment- 
water interactions is given by Johansson and Squires, later in this 
report. 



Figure 14. Nutrient sources and sinks, from Ross et al. 1984. 


84 











4. Red Tides 


One of the most distinguishing features of Tampa and Sarasota Bays 
is their occasional entrapment of red tides, or blooms of the unarmored 
dinoflagellate, Ptvchodiscus brevis . These blooms originate in offshore 
waters of the eastern Gulf of Mexico and move onshore with Loop Current 
eddys, wind, and nearshore currents. Once inshore, the blooms 

proliferate over huge areas, at times breaking into distinct cells and 
coalescing into larger masses at other times. The blooms occur once or 
twice every year or two. While there is no evidence that the frequency 
of blooms is greater than in past years there has been speculation that 
the duration of an inshore bloom may be prolonged by nutrient enrichment 
or other factors attributable to urbanization. Blooms cause fish kills, 
defaunate the benthos, and contaminate shellfish by oxygen depletion and 
the effect of their toxic metabolites. Aerosols produced in surf 
transport toxins inland causing human respiratory distress, and blooms 
generally inhibit tourism. Much needs to be learned about bloom 
initiation, maturation and transport, and about their ecological effects. 
Benthic infauna recolonize affected areas within 1-3 years, and recovery 
by other groups probably occurs over a 1-10 year period. These naturally 
occurring blooms, which may function similarly to wildfires in Florida’s 
fire-maintained pine flatwoods, also deserve study in order to understand 
brown tides better in northeastern estuaries, which apparently are 
expressions of cultural eutrophication. 

Urban Conditions Affecting Water Quality 

Discharge of sewage treatment plant effluent and urban stormwater 
runoff pose the greatest continuing threat to water quality of Tampa Bay. 
Characteristics of STP discharge were presented at the seminar by John V. 
Betz, and Giovannel1i*s paper elsewhere in this report summarizes his 
presentation on stormwater. 

The combined role of STP effluent and stormwater --plus 
agricultural and industrial loads-- was evaluated by Palmer and 
McClelland (1988) using a numerical model. The project, funded by the 
EPA with a grant for water quality studies under Section 205(j) of the 
Clean Water Act, concluded 

The problems in Tampa Bay appear to be related to nutrient 
enrichment and consequent high algal biomass: this can 
cause large dissolved oxygen variations and decreased light 
availability needed for seagrass growth. The nutrient and 
dissolved oxygen relationship along with the data and the 
modeling indicate that a bay-wide chlorophyll a value of 
25 ug/1 should be used as a maximum target for Tampa Bay in 
order to maintain good water quality. The historical data 
show that pockets of high chlorophyll a occur in 
Hillsborough Bay and the northwest corner of Old Tampa Bay. 

The modeling indicates that reduction of the chlorophyl1-a 
in these pockets will protect the rest of the bay system. 
Therefore, if the targets are met in these pockets, the bay 


85 





in its entirety would be expected to meet the targets. The 
modeling showed that the low flow and high flow simulations 
with no point sources were considerably different and that 
little is gained during the low flow season with the 
imposition of BMP’s [best management practices]. However, 
a significant improvement in the chlorophyll a 
concentration was predicted for Hillsborough Bay when 
agricultural and urban BMP’s were considered for the year 
2000 non-point source loadings. These simulations also 
included a limited nutrient discharge of the Alafia 
phosphate mines. It is recommended that in the 
Hillsborough Bay drainage basin, urban and agricultural 
BMP’s be implemented in order to reduce the nutrient load 
in Hillsborough Bay. For Old Tampa Bay, due to the nature 
and size of the watershed, only small improvements are 
predicted with the imposition of BMP’s. The non-point 
source simulations also indicate that the benthic fluxes of 
oxygen demand and of nutrients make a considerable 
difference in the condition of the bay. In particular, 
reduction of the fluxes to the low flow values for the high 
flow simulations resulted in a significant improvement in 
the bay. 

The DER report’s conclusion that BMP’s may not significantly 
improve the bay speaks to the enormity of stormwater impact, if the 
report is a valid assessment. If it is not, much more evaluation will be 
needed. As the DER report acknowledged, point source impacts were not 
incorporated in the 1988 water quality assessment. Details of industrial 
discharges and major water quality impacts to the bay are given in 
Phillips et al., elsewhere in this report. 


WATER QUALITY ISSUES IN BAY MANAGEMENT 


Since 1972, state law requires domestic waste water disposal 
facilities discharging into tidal waters of west-central Florida 
(including Tampa and Sarasota Bays) to provide advanced waste water 
treatment (AWT). A modified version of the law is in effect today, 
although a period between 1980-81 and 1987 passed in which AWT 
requirements were relaxed and the Florida Department of Environmental 
Regulation was instructed to specify water-quality based effluent 
limitations (WQBEL) on a case by case basis. The WQBEL approach operates 
on the principle that a receiving water can only accept a certain load, 
irrespective of source, and that decisions are needed to allocate 
increments of waste load to specific sources. 

Such waste load allocations could also be based on best available 
technology or impacts to living resources. In any case, some method is 
needed to analyze the combined effects of existing or proposed loads and 
the DER has used a numerical model of circulation and water quality for 
that purpose (although their original intent to base specific waste load 


86 



allocations on model outputs has been modified by reinstatement of AWT 
requirements). Critics of the model’s applications to waste load 
allocations support the scientific value of models and have called for a 
more comprehensive, ecosystem model of Tampa Bay, but challenge the 
concept of setting specific discharge limits using existing models which 
do not more completely address living resources, such as seagrasses. A 
new bay management program undertaken by the Southwest Florida Water 
Management District (see Perry’s paper in this report) may be able to 
enhance existing models and begin development of an ecosystem model. 

Either model could be used to incorporate ecological processes 
affecting water quality. Industrial inputs could be evaluated in terms 
of their cumulative impact, which if done for power generating stations 
alone would advance our ability to site new facilities or expand existing 
ones. The inputs of rivers must also be modelled with better accuracy. 
Ongoing basin-river-estuary studies in the Little Manatee River will be 
especially useful in this regard. Such inclusive models will be 
difficult to develop but are necessary to answer the fundamental bay 
management issues of what to improve, to what extent, and when, in order 
to gain how much benefit? 


87 


LITERATURE CITED 


Boler, R. (editor). 1986. Hillsborough County water quality, 1984-1985. 
Hillsborough Co. Env. Prot. Comm., Tampa. 205 pp. 

City of Tampa. 1988. An ongoing survey of Halodule wrightii , Ruppia 
marrtima, and the alga Caulerpa prolifera in Hillsborough Bay, Fla. 
Initial assessment and design. Dept. San. Sewers, Bay Study Group. 

Estevez, E.D. 1984. Summary of scientific information, Charlotte Harbor 
estuarine ecosystem complex. Final Rep. to Southwest Fla. Reg. Plan. 
Council, Ft. Myers. 2 vol. 

Fanning, K.A. and L.M. Bell. 1985. Nutrients in Tampa Bay, pp. 109- 
129. In, S.F. Treat et al. (eds) Proceedings Tampa Bay Area Scientific 
Information Symposium. Fla. Sea Grant Rep. No. 65, Bellwether Press. 

Fanning, K.A., J.A. Breland, II and R.H. Byrne. 1982. Radium-226 and 
radon-222 in the coastal waters of west Florida: high concentrations and 
atmospheric degassing. Science. 215:667-670. 

Hand, J., V. Tauxe and J. Watts. 1986. Florida water quality 

assessment, 1986. 305(b) Technical Report. Fla. Dept. Environ. Regul., 

Tallahassee. 235 pp. 

Lewis, R.R. Ill and E.D. Estevez. 1988. Ecology of Tampa Bay -- an 
estuarine profile. U.S. Fish. Wildl. Serv., Biol. Serv. Program. 

Palmer, S.L. and S.I. McClelland. 1988. Tampa Bay water quality 
assessment - [205(j) water quality study]. Fla. Dept. Environ. Regul. 
Water Quality Tech. Ser. Vol. 3, No. 17, Tallahassee. 

Ross, B.E., M.A. Ross and P.D. Jerkins. 1984. Wasteload allocation 
study, Tampa Bay, Fla. Final Report to Fla. Dept. Environ. Regulation. 
USF Center for Math. Models, Tampa. 4 vol. 

Santos, S.L. and J.L. Simon. 1980. Response of soft-bottom benthos to 
annual catastrophic disturbance in a south Florida estuary. Mar. Ecol. 
Progr. Ser. 3:346-355. 


88 









BIOLOGY AND EUTROPHICATION OF TAMPA BAY 


Roy R. Lewis III 
Mangrove Systems, Inc. 
Tampa, Florida 


BIOLOGICAL CHARACTERISTICS 


Primary Producers 

There are four principal groups of phytoplankton in Tampa Bay: 
phytomicroflagel1ates, diatoms, dinoflagellates and blue-green algae. 
The early studies of phytoplankton in the bay have been summarized by 
Steidinger and Gardiner (1985). These studies were initiated in response 
to the problem of blooms (cell counts usually greater than 50,000 per 
liter) of toxic dinoflagellates ( Ptvchodiscus brevis ). known as "red 
tides", particularly the massive blooms of 1946-1947. The findings of 
all studies to date can be summarized as follows: 

1. A north-to-south, or head-to-mouth, gradient exists in 
phytoplankton species numbers. In general, as one moves from the 
less saline upper portions of the bay to the more saline lower 
portions of the bay, water clarity and phytoplankton species 
numbers (or "richness") increase, while nutrient levels, 
chlorophyll ’a’, and total phytoplankton cell counts decrease. 
The frequency of phytoplankton blooms and the eutrophic and turbid 
nature of the upper bay, particularly Hillsborough Bay, have been 
a common observation in recent years (Federal Water Pollution 
Control Administration [FWPCA] 1969; Simon 1974). 

2. Nanoplankton (5-20 urn) generally are the dominant size class of 
the phytoplankton. Small diatoms and mi crofl agel 1 ates 
predominate, except when certain seasonal, monospecific blooms of 
species of blue-green algae ( Schizothrix ) or dinoflagellates 
( Gvmnodinium nelsonii , Ceratium hircus . Procentrum micans , 
Gonvaulax spp. and others) dominate in Hillsborough Bay and Middle 
Tampa Bay. 

3. At least 272 species of phytoplankton occur in the bay: the 
majority (167) are diatoms. 

4. Short-term fluctuations in species composition and standing crop 
are common. Seven-fold to ten-fold differences are reported 
within one tidal cycle. 


89 














5. 


The majority of the bloom species are resident in the bay but 
significant blooms occasionally occur due to species which invade 
from the Gulf of Mexico. Blooms of the toxic species Ptvchodiscus 
brevis originate 16-60 km offshore, for reasons as yet unclear, 
and are carried into the bay. Between 1946 and 1982, such 
invasions occurred at least 12 times. 

6. Many of the previous studies utilized analytical procedures which 
limit the quantitative comparison of all data; some uniform 
sampling strategy and analytical procedures are needed to make 
future data more usable. Quarterly sampling and ignoring the 
nanoplankton in taxonomic and production studies are two of the 
problem areas.Primary production studies of phytoplankton in Tampa 
Bay have been summarized by Johansson, Steidinger and Carpenter 
(1985). Table 1 lists the annual rates reported in several 
studies using three different methods. Whether the different 
values over time reflect a real increase in primary production by 
phytoplankton or simply the results of different methods cannot be 
determined at present. 


Table 1. Estimated annual Dhytoplankton production rates in the Tampa 
Bay system (g C/m 2 /yr). From Johannson et al. 1985. 


Dates 

Old 

Hillsborough 

Middle 

Lower 

and Methods 

Tampa Bay 

Bay 

Tampa Bay 

Tampa 1 

1968 

170 

270 

170 

120 

Chlorophyll + 

1 ight 




1965-67 

430 

610 

440 

220 

Oxygen 





1969-72 

290 

580 

490 

180 

Chlorophyll + 

light 




1973-83 


620 

620 


Carbon isotope 





Earlier data may be of limited value due to the methods used (lack 
of grinding), which probably produce an underestimate of chlorophyll ’a’ 
in eutrophic waters; however, it is reasonable to assume a real increase 
in phytoplankton production due to eutrophication. Annual production of 
340 g C/m 2 is suggested as a reasonable estimate for phytoplankton 
primary production in the deeper portions of Tampa Bay, and 509 g C/m 2 
for shallower portions, based on the available data (Johansson et al. 
1985). 


90 






Epiphytic (living on plants) microalgae are treated here as a 
group separate from other benthic algae because of their apparent 
importance in food webs in other Florida estuarine systems (Fry 1984), 
and because those found growing on seagrass leaves in Tampa Bay have 
received some study (Dawes 1985). The most common epiphytes are species 
of Champia , Lomentaria , Polvsiphonia , Acrochaetium , Fosliella , Hypnea , 
Spyridia , Cladosiphon . Ectocarpus and Cladophora . The possible 
importance of epiphytic algae in the food web and the general health of 
seagrasses in a eutrophic estuary like Tampa Bay are discussed later. It 
is sufficient to note here that the abundant caridean shrimp and 
amphipods found in Tampa Bay seagrass meadows have been shown elsewhere 
to depend heavily on seagrass algal epiphytes as a source of food (Orth 
and Van Montfrans 1984). It is likely that the same dependence would be 
found here. 

Macroalgae are abundant in Tampa Bay, and the 221 identified 
species from the bay represent a greater diversity than that reported for 
any other estuary in Florida (Dawes 1985). Red and green algae 
predominate, with brown algae being more abundant in the winter and early 
spring, although still not dominant. 

Most studies of macroalgae in the bay have been taxonomic or 
physiological in nature (Dawes 1985); have focused on the overabundance 
of certain pollution indicator species (Ulya spp., Gracilaria spp.) which 
cause aesthetic problems (FWPCA 1969); have been implicated in the 
elimination of seagrass meadows from certain parts of the bay (Guist and 
Humm 1976); or have anecdotally reported consumption of macroalgae by 
manatees (Lewis, Carlton and Lombardo 1984). The FWPCA (1969) studied 
the abundance and distribution of macroalgae in Hillsborough and Old 
Tampa Bay to determine the source of odor problems reported by residents 
along the western shore of Hillsborough Bay. The study concluded that 
the odors were caused by excessive nutrient concentrations which led to 
massive blooms of the macroalga Gracilaria tikvahiae . This species, in 
turn, was killed by normal salinity reductions during times of heavy 
rainfall and decayed to produce the odor. 

Rates of primary production by Tampa Bay macroalgae, of 
approximately 70 g C/m 2 /yr, have been measured in both laboratory and 
field experiments (Hoffman and Dawes 1980; Dawes 1985). The data are 
very sparse, and much additional work is needed, especially seasonal 
field measurements. 

Seagrasses are submerged flowering plants with true roots and 
stems, and are quite different from "seaweeds" (macroalgae), which are 
nonflowering algal species without true roots. Lewis, Durako, Moffler 
and Phillips (1985) reported that five of the seven species of seagrass 
known from Florida are found in Tampa Bay: Thalassia testudinum (turtle 
grass); Svrinqodium filiforme (manatee grass); Halodule wrightii (shoal 
grass); Ruppia maritima (widgeon grass); and Halophila engelmannii (star 
grass). 


91 

























SEAGRASS MEADOW TYPES 


MBS(P) 


HF(P) 




H • MALODULE R • RUPPIA 3 • 3 YRINQODIUM T THALA33IA 


Figure 1. Seagrass meadow types. MBS(P) - mid-bay shoal perennial; 

HF(P) - healthy fringe perennial; $F(P) - stressed fringe 
perennial; (E) - ephemeral; C(P) - colonizing perennial. From 
Lewis et al. 1985. 


92 




























Seagrass meadows now cover 5,750 ha of the bottom of the bay. 
Based on historical aerial photography and maps, it is estimated that 
seagrasses once covered 30,970 ha of the bay. This 81% loss has had 
severe effects on the bay’s fisheries (Lombardo and Lewis 1985). 

Box cores taken at 18 stations in the bay over a one-year period 
(Lewis et al. 1985) showed that seagrass meadows in Tampa Bay are largely 
monospecific, with approximately 40% being turtle grass, 35% shoal grass, 
15% manatee grass, and 10% widgeon grass. Star grass was seen 
infrequently. Lewis et al. (1985) defined five types of seagrass meadows 
in the bay, based on location, form, and species composition (Figure 1): 
1) mid-bay shoal perennial, MBS(P); 2) healthy fringe perennial, HF(P); 
3) stressed fringe perennial, SF(P); 4) ephemeral, E; and 5) colonizing 
perennial, C(P). The idealized cross-sections in Figure 2 are derived 
from actual transects established during 1979-1980 (Lewis and Phillips 
1980). It is hypothesized that Types 2-4 are stages in the eventual 
disappearance of a seagrass meadow due to human-induced stress, as 
illustrated by the arrows in Figure 1. 

As noted by Lewis et al. (1985), most of the work to date on 
seagrass meadows in Tampa Bay has concentrated on descriptive biology 
(distribution, reproduction, infaunal communities). The elucidation of 
the functional role of seagrass meadows in the bay in terms of value as a 
food source (direct herbivory, detrital, drift and epiphytic algal 
component) and habitat is being initiated only now, primarily in relation 
to larval fish use. Even estimates of total primary production by 
seagrasses are hampered by the lack of comprehensive baywide seasonal 
data. 


It is likely that seagrass meadows in Tampa Bay are important 
habitat for benthic invertebrates and certain juvenile species of fish. 
Virnstein, Mikkelsen, Cairns and Capone (1983) noted in their studies in 
the Indian River that seagrass meadows had a density of infaunal 
invertebrates three times that of unvegetated sediments, and that 
epifaunal organisms were 13 times as abundant in seagrass as in sandy 
areas. Zieman (1982) noted that eight sciaenid species have been 
associated with seagrass meadows in southwestern Florida, and that 
juvenile spotted seatrout ( Cvnoscion nebulosus), spot ( Leiostomus 
xanthurus ) and silver perch ( Bairdiella chrvsoura ) are commonly found in 
seagrass beds. Sheepshead ( Archosargus probatocephalus ) and snook 
( Centropomus undecimal is ) also use seagrass meadows as habitat during 
their life cycles (Odum and Heald 1970; Gilmore et al. 1983). 

Similar data for seagrass meadows in Tampa Bay are sparse, but the 
existing data support the importance of seagrass meadows as habitat for 
fish and invertebrates. Studies of fish populations in Tampa Bay 
indicate that seagrass meadows are one of several important nursery 
habitats for juvenile fish (Springer and Woodburn 1960; Comp 1985). 
Collections by Springer and Woodburn (1960) at two areas containing mixed 
seagrass and algae had the highest number of species (108 and 93, 
respectively, of a total of 253 species). The lowest number of species, 
48, was reported from an unvegetated sandy beach station. 


93 












The vegetation of emergent wetlands in Tampa Bay consists of 

various mixtures of five major plant species, two of which are tidal 
marsh species, black needlerush (Juncus roemerianus ) and smooth cordgrass 
( Spartina alterniflora ), and the remaining three being mangroves. Minor 
species in these tidal marshes include leather fern ( Acrostichum 

danaeofolium ), the brackish water cattail ( Typha domingensis h and 
bulrush ( Scirpus spp.). 

Estimates of the percentage of the total emergent wetlands which 
are tidal marsh vary from 10% to 18% (Estevez and Mosura 1985; E. 

Pendleton, [U.S. Fish Wildlife Service, Slidell, Louisiana] pers. 
comm.). Mangroves are the dominant vegetation, but periodic freezes 

allow substantial areas of tidal marsh to persist as cold-sensitive 
mangroves are pruned or killed (Estevez and Mosura 1985). These authors 
also noted that "regrettably little is known of the organization or 
functioning of tidal marshes in Tampa Bay". 

In contrast to tidal marshes, mangrove forests on the bay have 

received some study (Estevez and Mosura 1985), although it has been 
primarily descriptive in nature. The forests are composed of three 

species (Figure 2); red mangrove ( Rhizophora mangle ), black mangrove 

( Avicennia germinans ). and white mangrove ( Laguncularia racemosa). 
Unlike mangrove forests farther south (Odum and Heald 1972), mangrove 
forests on Tampa Bay are composed of a mixture of all three species, and 
while exhibiting natural zonation similar to that described by Davis 

(1940), have some unique features (Estevez and Mosura 1985; Lewis et al. 
1985). 


The latitude of Tampa Bay is near the northern limit of the 
distribution of mangroves, and low temperature stress is common in the 
mangrove forests. Repetitive freezes can intensify temperature effects 
on the structure of the forest. Initially, the canopy is partially 
destroyed; if another freeze quickly follows, the damaged trees are 
killed. In recent years, two freezes have occurred relatively close 
together (1977 and 1983). During January 1977, a minimum temperature of 
-5°C was reached and snow fell for the first time in more than 100 years. 
The Christmas freeze of 1983 involved two days during which the 
temperature in Tampa fell to -6.7°C, followed by -7.2°C the next day. 
Such low temperatures had not occurred in Tampa since the historical 
freeze of 1894-1895 dealt a serious blow to the then flourishing citrus 
industry in Florida. The freezes in 1977 and 1983 caused significant 
losses of mangroves, and the total area of tidal marsh on the bay may 
increase as more cold-tolerant marsh plants invade areas left barren by 
the death of the mangroves (Figure 3). Selective survival of mangroves 
has been observed during a less severe frost or freeze, with the black 
mangrove having the greatest resistance to freeze damage and the white 
mangrove the least. The black mangrove is typically the largest diameter 
tree in the forest (Table 2), particularly in the fringe and overwash 
forests which are the dominant types in the bay. 


94 

















Figure 2. 


Healthy mangrove forest dominated by black mangroves 
( Avicennia germinans K Middle Tampa Bay, March 1983. 



Figure 3. Freeze damaged mangrove forest (dominated by black 
mangroves), Old Tampa Bay, April 1986. 



95 








Table 2. Mangrove tree size by species and forest type in Tampa Bay 
(Williamson and Mosura 1979). DBH - diameter at breast height, 
numbers in parentheses are sample sizes. 

CUMULATIVE MEAN DBH (cm) 


Forest type 

Fringe 

Overwash 

Tributary 


Rhizophora 

2.69 + 2.26 
(139) 

3.37 + 2.04 
(90) 

2.91 + 2.01 
(50) 


Avicennia 

4.59 + 3.16 
(186) 

5.27 + 1.37 

(7) 

1.85 + 0.99 

(17) 


Laguncularia 

2.31 + 2.64 
(203) 


2.57 + 0.38 

( 10 ) 


Although the necessary habitat utilization studies have not been 
conducted for Tampa Bay, the value of mangroves to Florida’s fisheries is 
well documented (Lewis et al. 1985). Mangroves are known to serve as one 
of several critical habitats in the life history of many fish and 
shellfish species important in commercial and recreational fisheries, 
including pink shrimp ( Penaeus duorarum ), redfish or red drum ( Sciaenops 
ocelJLatus), tarpon ( Meoaloos at1anticus h and snook ( Centropomus 
undecimal is ) (Odum, Mclvor and Smith 1982; Lewis et al. 1985; Haddad, 
this volume). 

All major rivers and streams entering the bay have floodplain 
forests and adjacent wetlands that drain eventually into the bay. These 
freshwater wetlands serve as the first of a series of filters to cleanse 
upland drainage before it enters the bay, and they also act as 
contributors of dissolved and particulate organic matter and nutrients. 

Typical of these wetlands are those bordering the Alafia River. 
Clewell, Goolsby and Shuey (1983) described these wetlands as supporting 
409 plant species, including 84 tree species, dominated by red maple 
( Acer rubrum ) and swamp tupelo ( Nvssa biflora ). 

Total streamflow input to Tampa Bay is estimated to average 2,011 
cfs (Flannery, this report). If it can be assumed that total organic 
carbon concentration (TOC) averages 10 mg C/1 (Dooris and Dooris 1985), 
then TOC input via streamflow would be 2 x 107 kg C/yr. TOC measurements 
of this sort are typically made on unfiltered water samples, but do not 
take into account bedload transport of organic material derived from 
adjacent wetlands and uplands, or pulse events when large amounts of 
organic matter may be moved in a relatively short period of time. For 
this reason, the above input value should be considered conservative. 


96 



















Total net primary production (carbon reduced by photosynthesis) by 
natural plant communities in Tampa Bay (listed by category in Table 3) is 
estimated at 478.2 x 10° kg/yr. These figures indicate that Tampa Bay 
can be characterized as a phytoplankton-based system when compared to 
other sources of net primary production. By virtue of their high annual 
production, mangroves are the second most important primary producer in 
the estuary. 

In addition to primary production, organic material can be 
transported to the bay from outside sources by streamflow, sewage 
discharges, urban runoff from pavement, rainfall, and groundwater 
discharge. These values account for a total input of organic carbon of 
92.7 x 10° kg/yr, or about 25% of the amount produced by photosynthesis 
(or marine plants) in the bay. This figure was probably much higher 
prior to recent improvements in industrial and municipal discharges, and 
substantial deposits of residual organic matter are still present in bay 
sediments (Ross, Ross and Jerkins 1984). The estimate by those authors 
of current allochthonous sources of organic carbon is somewhat less, 66.7 
vs. 92.7 x 10 6 kg/yr. 


Table 3. Estimated annual production of primary producers based on areal 
coverage in the Tampa Bay system (modified from Johansson 
et al. 1985). 


PRIMARY 

PRODUCER 

PRODUCTION 
(g C/m 2 /yr) 

Seagrass and 
epiphytes 

730 

Macroalgae 

70 

Benthic 

microalgae 

150 

Mangrove 

forests 

1,132* 


AREA TOTAL PRODUCTION PERCENT 

(km 2 ) (g C/yr x 10 6 ) OF TOTAL 

57.5 42.0 8.5 

100.0 7.0 1.4 

200.0 30.0 6.0 

64.5** 73.0 14.7 


Tidal marshes 

300 

Phytoplankton 

340 

(areas >2m deep) 


Phytoplankton 

50 

(areas <2m deep) 



10.5** 

3.2 

0.6 

864.0 

293.8 

59.1 

96.0 

48.0 

9.7 


Riverine forests -- no data available. 


*Estevez and Mosura 1985. 

**Assuming 14% of the bay’s emergent wetlands are tidal marsh. 


97 


Secondary Production 


Secondary producers are the animal communities, either herbivorous 
or carnivorous, that consume the organic carbon in an area. A simplified 
food web for the bay is shown in Figure 4. Ideally, one should be able 
to measure the amount of fish or crab biomass produced over a period to 
time; this is total secondary production. Data on secondary production 
in Tampa Bay have not been generated accurately. 

In order to understand how the bay works, it will be important to 
quantify both the types and amounts of primary and secondary production. 
Simply having large amounts of both may not necessarily be ideal. A bay 
ecosystem with a large variety of plant and animal species actually may 
require less organic material input. The typical "green pea soup" 
appearance of a polluted pond or sewage treatment plant lagoon is an 
example of high primary production that also indicates an unbalanced 
system. Proper management of Tampa Bay to provide stable, balanced 
populations without abnormal algal blooms and fish kills will require a 
better understanding of both primary and secondary production. 

The most extensive study of holoplankton to date (Hopkins 1977) 
provides much useful data, but the author emphasized that collections 
were taken only the the surface of the bay once every three months 
(quarterly) for one year. The data are of limited value in describing 
long term cycles but are essential as a first step in describing the 
general characteristics of the bay zooplankton. Thirty-seven species of 
holoplankton were identified in the study, and were grouped into three 
categories based on abundance. Mean biomass of all zooplankton was 39.6 
mg dry wt/m 3 . The dominant species were three copepods ( Qithona 
colcarva, Acartia tonsa , Paracalanus crassirostris h which made up 56% of 
the zooplankton biomass. 

Meroplankton is composed of two groups, invertebrate and fish 
meroplankton (ichthyoplankton). Meroplankton data for Tampa Bay have 
been summarized by Weiss and Phillips (1985). Hopkins (1977), in 
sampling for holoplankton, found that 19% of total zooplankton number and 
8% of the total biomass (3.2 g dry wt/m 3 ) were meroplankton. 

The benthic community consists of animals that live in the 
sediment as infauna by burrowing or forming permanent or semi-permanent 
tubes extending just above the sediment surface; animals that live on the 
sediment surface either as mobile epifauna or sedentary epifauna; and 
animals that form specialized communities such as oyster reefs or 
live-bottom communities. 

Taylor (1973), Simon (1974), and Simon and Mahadevan (1985) 
summarized the benthic studies conducted in Tampa Bay. These studies 
have resulted in the following general conclusions regarding this group 
of invertebrates in Tampa Bay: 


98 












Figure 4. 


Idealized marine food 


chain 


elements. 


99 





































































































1. The estuary supports "an extremely abundant and diverse assemblage 

of bottom organisms, except in Hillsborough Bay, dredged regions 
of Boca Ciega Bay, and a system of inland canals developed in 
upper Tampa Bay" (Taylor 1973). Taylor listed 207 species of 
polychaetes, 231 species of mollusks, and 29 species of 

echinoderms found in the bay. Simon and Mahadevan (1985) stated 
that approximately 1,200 infaunal and epifaunal species (excluding 
meiofauna) occur in the bay. 

2. Seasonal fluctuations in the abundance and diversity of these 
organisms are pronounced. Seasonal variability in benthic 
populations is high and densities can range from zero to 
200,000/mS particularly in areas of pollution-related stress. 

3. Seagrass beds have declined, with a concomitant decrease in faunal 
diversity. 

4. Opportunistic and "pollution indicator" species are abundant, 

particularly in Hillsborough Bay where pollution problems have 
been well documented for many years. Both Santos and Simon (1980) 
and Dauer (1984) noted that parts of the bay periodically undergo 
catastrophic disturbance due to anoxia (lack of oxygen). This 

condition was first documented by the FWPCA (1969) and the 
National Marine Fisheries Laboratory (Taylor, Hall and Saloman 
1970) during the mid-1960s, and is similar to conditions reported 
in Chesapeake Bay (Officer, Biggs, Taft, Cronin, Tyler and Boynton 
1984) as far back as the 1930s. 

5. Sediment type appears to be a controlling factor in determining 
infaunal distributions in the bay. Bloom, Simon and Hunter (1972) 
sampled along three shallow shoreline transects in Tampa Bay, each 
with a distinct sediment type (mud, sand, muddy sand). They 
concluded that benthic assemblages along two of the transects were 
distinct, and the assemblage along the third was a composite of 
the other two. 

6. A general increase in species richness and decrease in total 
population abundance are evident on a north-to-south gradient in 
the bay. 

Springer and Woodburn (1960) listed 253 species of fish found in 
the Tampa Bay area. Additional studies raised the total number to 312 
(Springer and McEarlean 1961; Moe and Martin 1965). Comp (1985) noted 
that many of these were offshore species and would likely never be found 
in the bay. He prepared a list of 203 species which were actually 
collected within the bay. He believed that only 125 of these could be 
considered common inhabitants, and although the list indicates a diverse 
fish assemblage, ten or fewer species usually made up the majority of the 
fish caught in sampling programs. Table 4 lists the ten most common fish 
in Tampa Bay in terms of numerical abundance in collections made with 
standard gear. As both Springer and Woodburn (1960) and Comp (1985) 
emphasized, the standard gear used for sampling of fishes in the bay is 


100 


biased toward capturing smaller, less mobile species. For example, 
sharks and rays are abundant in Tampa Bay, but are rarely sampled due to 
their mobility and size. Even mullet are probably undersampled, although 
they are one of the most abundant species in the bay. 

Tampa Bay is a nursery area for the larvae and juveniles of 79 
resident and migratory fish species. Most spawning occurs during the 
spring and early summer in either the nearby Gulf or the bay proper, 
usually in higher salinity areas. During and following these spawning 
periods, the larval and juvenile fish typically migrate into shallow, 
protected, low salinity nursery areas of the bay to feed and mature (Comp 
1985; Lewis et al. 1985). 

Only two species of marine reptiles are common in the bay, the 
diamondback terrapin ( Malaclemvs terrapin macrospilota ) and the mangrove 
water snake ( Nerodia fasciata compressicauda ). Both are common in 
localized areas, but have not been studied. Loggerhead turtles (Caretta 
caretta) are occasionally observed in the bay on the Gulf side of Egmont 
Key (Reynolds and Patton 1985). 


Table 4. The ten dominant fish species in Tampa Bay, listed in 
approximate order of abundance, with notation as to area of the 
bay where found (modified from Springer and Woodburn 1960; 
Finucane 1966; Comp 1985). 

MIDDLE 

COASTAL LOWER TAMPA BAY TAMPA BAY HILLSBOROUGH 
BEACHES medium to medium & MCKAY BAYS 

SPECIES high salinity high salinity salinity low salinity 


Tidewater silverside X 

Menidia peninsulae 

Bay anchovy 
Anchoa mitchilli 

Scaled sardine X 

Harenoula .iaguana 

Striped mullet 
Mugil ceohalus 

Pinfish 

Lagodon rhomboides 

Longnose killifish 
Fundulus similis 

Spot 

Leiostomus xanthurus 


X XX 

X XX 

X X 

X XX 

X XX 

X XX 

X XX 


101 

























Table 4. continued. 


SPECIES 


MIDDLE 

COASTAL LOWER TAMPA BAY TAMPA BAY 

BEACHES medium to medium 

high salinity high salinity salinity 


HILLSBOROUGH 
& MCKAY BAYS 
low salinity 


Silver perch X X 

Bairdiel1 a chrvsoura 


Silver jenny X X 

Eucinostomus quia 

Code goby X X 

Gobiosoma robustum 


Seabirds and wading birds are a very visible and important 

component of the animal life of the bay. Because they are relatively 

easy to observe, counts and species observations are abundant. 

Eighty-three species of birds are associated with marine habitats in the 
bay. Many of these use certain bay habitats for nesting and raising 
young, and also wade in the shallows or dive in deeper waters to feed on 
fish and invertebrates. 

The Brown Pelican (Pelecanus occidental is ) is particularly well 
studied (Woolfenden and Schreiber 1973; Schreiber and Schreiber 1983). 
The adults nest in the canopy of mangroves on natural or artificial 

islands in the bay where they are protected from mammalian predators 
(e.g., raccoon, Procvon lotor ) which typically do not swim across water 
barriers. 

The total breeding population of colonial birds in Tampa Bay is 
estimated to be 75,000 pairs, two-thirds of which are Laughing Gulls 
(Paul and Woolfenden 1985). The Laughing Gull population is estimated to 
be one-third of the entire breeding population in the southeast United 
States. The Brown Pelican population of 2,700 to 3,000 breeding pairs 
represents nearly one-third of the entire Florida population. In 1983, 
an estimated 10,200 pairs of White Ibis were present in one large colony 
at the Alafia River (Paul and Woolfenden 1985). 

McKay Bay, in the northeast part of Tampa Bay, typically supports 
a winter population of almost 25,000 marine birds, which during eleven 
years of censusing, have included 75 species. Almost 80% of these are 
five species: Lesser Scaup, Ruddy Duck, Dunlin, Short-billed Dowitcher, 
and Western Sandpiper (Paul and Woolfenden 1985). 

Although some species which formerly nested in the bay have 
returned recently (Reddish Egret in 1974, Roseate Spoonbill in 1975), 
recent population declines in many species are apparent. Paul and 


102 












Woolfenden (1985) listed red tides, parasite outbreaks, dredge and fill 
activities, pesticide use, and oil spills as having generally negative 
effects on bird abundance. Waterfowl surveys of the bay have indicated a 
sharp deline in the winter population of Lesser Scaup, from 105,900 in 
1976 to 8,400 in 1979. Major dredging in Hillsborough Bay is implicated 
as a possible cause of the decline, because over 400 ha of open water 
habitat was lost during this period as a consequence of spoil island 
creation. 

Reynolds and Patton (1985) have summarized the existing 
information on marine mammals of the Tampa Bay area. Only two species 
are normally found within the bay, the bottlenose dolphin ( Tursiops 
truncatus ) and the West Indian manatee ( Trichechus manatus ). The 
bottlenose dolphin is a year-round resident and the local population is 
estimated at 100-200 individuals, found in small herds of three to six 
animals (Reynolds and Patton 1985). 

In a baywide survey over a period of one year, Patton (1980) found 
that numbers of manatees varied seasonally; a maximum of 55 was observed 
in the winter. They appeared to congregate around industrial thermal 
discharges into the bay. The largest single aggregation was 42 
individuals, observed around the mouth of the Alafia River in February 
1980. Lewis et al. (1984) observed manatees feeding on macroalgae in the 
same area in January 1981. 

There is a general absence of studies on ecological relationships 
in the bay. Unlike studies in Apalachicola Bay (Livingston 1984), most 
scientific work in Tampa Bay has been basically descriptive, or has 
concentrated on a single structural or functional aspect of the bay’s 
ecology. Future studies need to address four topics concerning 
ecological relationships in the bay: 1) energy sources; 2) abiotic 
controls in communities; 3) plant and animal interactions; and 4) 
fisheries habitats. 

The flow of energy from the sun through plants to the animal 
communities of the bay is illustrated in Figure 5. None of the boxes or 
arrows have numbers associated with them because the specific quantities 
of energy contributed to the various animal groups by the major plant 
types have not been made. Table 1 lists phytoplankton as the source of 
68.8% of the bay’s primary production. This does not mean that 
phytoplankton provide 68.8% of the energy consumed by animals in the bay, 
because the quantity of energy captured by phytoplanktonic photosynthesis 
that is subsequently lost to sedimentation and flushing to the bay is 
unknown. Because of eutrophication, it is likely that much phytoplankton 
productivity is incorporated as organic deposits in the bottom of the 
bay, and may contribute to anoxic conditions reported in Hillsborough Bay 
(Johansson and Squires, this volume). Similar events have been 
attributed to high phytoplankton productivity in Chesapeake Bay (Officer 
et al. 1984). 


103 






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104 


Figure 5. Generalized food web for Tampa Bay. 

















































































































The annual cycles of temperature and rainfall, and the common 
events of red tides, hurricanes, drought and frost, are the basic 
controlling factors for all life cycles in the bay. However, no attempts 
have yet been made to statistically correlate physical factors to 
biological variables in the bay. Within the anlayses of some individual 
studies, distinct correlations are demonstrated. Without these analyses, 
conclusions as to cause and effect in bay processes can be erroneous. An 
example is the general anecdotal observation that water clarity in the 
bay is improving; this is often attributed to improved sewage treatment 
at such plants as the City of Tampa’s Hookers Point facility. Trends in 
water clarity and chlorophyll a (Estevez, this report) tend to support 
these observations. What is not taken into account is the fact that 
several recent winters have been the coolest in 100 years, and rainfall 
has been less than average. Both of these climatological features could 
potentially contribute to reduced phytoplankton populations and increased 
water clarity. To illustrate, Flint (1985), in examining eleven years of 
biotic and abiotic data for Corpus Christi Bay, noted that episodic 
events (floods, hurricanes) stimulated estuarine productivity and thus 
represented a significant forcing factor to the estuary. He stated (p. 
168) that "without the reconstruction of a long-term data set ... these 
perceptions of ecosystem function could not have been developed". 

Unfortunately, we do not have simultaneous, long-term data sets of 
abiotic and biotic information from which to draw similar conclusions 
about Tampa Bay. Although large amounts of abiotic data are collected, 
there has been no similar effort toward the collection of concurrent 
biotic community data. The problems of understanding the role of 
physical parameters in bay processes are immense but without that 
understanding, decisions on bay management will continue to be made on 
the basis of symptomatic, rather than causative, considerations. 

In addition to their role as sources of energy, plant communities 
in the bay are important as habitat for animals. Certain species are 
found in particular habitats at certain times of the year. For example, 
Brown Pelicans seek out the mangrove islands for nesting during the 
spring (Paul and Woolfenden 1985), and young pinfish are found in large 
numbers in seagrass meadows at about the same time (Springer and Woodburn 
1960). Quantitative sampling of fauna has been limited largely to 
benthic infauna in unvegetated habitats. The studies of polychaetes in a 
seagrass meadow (Santos and Simon 1974) and of invertebrates in a 
mangrove forest (Lewis 1983) are two of the few exceptions. 

The assumption is made that the loss of certain vegetated habitats 
has contributed to declines in fish and wildlife in the bay (Hoffman, 
Durako and Lewis 1985; Lewis et al. 1985; Paul and Woolfenden 1985), and 
that re-establishment of these plant communities would restore fish and 
wildlife populations to some higher numbers (Hoffman et al. 1985). 
Though most scientists would not disagree with these general assumptions, 
supporting data are not available for Tampa Bay. More importantly, the 
direction of restoration efforts should have a sound scientific basis in 
order to produce measurable results. 


105 


Eutrophication 


Eutrophication is defined as the process of increasing dissolved 
nutrient concentrations to a point where nutrient enrichment produces 
certain characteristic responses in a water body. These responses 
include algal blooms, noxious odors, declines in dissolved oxygen, and 
periodic fish kills. Such characteristic responses have been observed in 
Tampa Bay, particularly Hillsborough Bay, for 20 years prior to the FWPCA 
(1969) documentation of nutrient enrichment from partially treated sewage 
discharges as the primary cause. 

Subsequently, over $100 million was spent to upgrade the Hookers 
Point sewage treatment facility from primary to advanced or tertiary 
treatment. The upgraded plant came on line in 1979. After that, other 
studies done by the Florida Department of Environmental Regulation, the 
U.S. Geological Survey, and the City of Tampa concluded that urban runoff 
from streets and parking lots could contribute up to 25% of the 
biochemical oxygen demand, 35% of the suspended solids, and 15% of the 
nitrogen loading to Hillsborough Bay (Garrity, McCann and Murdoch 1985). 

An additional aspect of the problem was added by Fanning and Bell 
(1985) when they suggested that nutrient fluxes from the bay’s sediments 
could be important as sources of nutrients to the water column. These 
authors illustrated that ammonia (NH 3 ) in Tampa Bay reached values higher 
than those found in other studied estuaries. In addition, the ratio of 
ammonia to total inorganic nitrogen (NO 3 - + NO 2 - + NH 3 ) was quite high 
(0.84 + 0.12). Although declines in phosphorus concentrations have been 
documented for the bay, nitrogen concentrations in the water column have 
remained high (Johannson and Squires, this volume). 

Windsor (1985), examining existing water quality data for 28 
coastal areas of Florida, found only three in which nutrient enrichment 
was indicated and definite problems of oxygen depletion were observed: 
Perdido Bay, Tampa/Hillsborough Bay, and Biscayne Bay. 

Lewis et al. (1985) noted that eutrophication leading to 
microalgal and macroalgal blooms may have contributed to the decline in 
seagrasses in the bay due to reduction in downwelling light through 
competition and epiphytic algae loading on seagrass blades. Direct 
experimental evidence of this has been provided by Twilley, Kemp, Staver, 
Stevenson and Boynton (1985), where artificial nutrient loading leads to 
light attenuation by microalgae, epiphytic algae loading on leaves of 
macrophytes, and significant decreases in biomass of submerged 
macrophytes. Orth and Moore (1983) hypothesized that the significant 
loss of submerged aquatic vegetation in Cheseapeake Bay may be due, in 
part, to similar nutrient enrichment. 


106 



Fanning and Bell (1985) recommended that four areas of research be 
pursued to further clarify the problem of eutrophication in Tampa Bay: 

1. Long range coordinated nutrient sampling of the bay to accurately 
characterize conditions and detect changes; 

2. Sampling to determine pathways and rates of nutrient 
transformation; 

3. A study of interactions and exchanges of nutrients between the bay 
and the Gulf of Mexico; and 

4. Clarification of the role of sediments as sinks or sources of 
nutrients under various conditions. 


107 


LITERATURE CITED 


Bloom, S.A., J.L. Simon and V.D. Hunter. 1972. Animal-sediment 
relations and community analysis of a Florida estuary. Mar. Biol. 
13(1):43 - 56. 

Clewell, A.F., J.A. Goolsby and A.G. Shuey. 1983. Riverine forests of 
the south prong Alafia River system, Florida. Wetlands 2:21-72. 

Comp, G.S. 1985. A survey of the distribution and migration of the 
fishes in Tampa Bay. Pp. 393-425, In: S.F. Treat, J.L. Simon, R.R. Lewis 
and R.L. Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific 
Information Symposium [May 1982]. Burgess Publishing Co., Minneapolis, 
MN. Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Dauer, D.M. 1984. High resilience to disturbance of an estuarine 

polychaete community. Bull. Mar. Sci. 34(1):170-174. 

Davis, J.H. 1940. The ecology and geologic role of mangroves in 

Florida. Pap. Tortugas Lab. No. 32. Carnegie Inst. Wash. Publ. 
517:305-412. 

Dawes, C.J. 1985. Macroalgae of the Tampa Bay estuarine system. Pp. 

184-209, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. Whitman, Jr. 

(eds.) Proceedings, Tampa Bay Area Scientific Information Symposium [May 
1982]. Burgess Publishing Co., Minneapolis, MN. Available from Tampa 
BASIS, P.0. Box 290197, Tampa, FL 33687. 

Dooris, P.M. and G.M. Dooris. 1985. Surface flows to Tampa Bay: 
quantity and quality aspects. Pp. 88-106, In: S.F. Treat, J.L. Simon, 
R.R. Lewis and R.L. Whitman, Jr. (eds.) Proceedings, Tampa Bay Area 
Scientific Information Symposium [May 1982]. Burgess Publishing Co., 
Minneapolis, MN. Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 
33687. 

Estevez, E.D. and L. Mosura. 1985. Emergent vegetation. Pp. 248-278, 
In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. Whitman, Jr. (eds.) 
Proceedings, Tampa Bay Area Scientific Information Symposium [May 1982]. 
Burgess Publishing Co., Minneapolis, MN. Available from Tampa BASIS, 
P.0. Box 290197, Tampa, FL 33687. 

Ewald, J.J. 1969. Observations on the biology of Tozeuma carolinense 
(Decapoda, Hippolydidae) from Florida, with special reference to larval 
development. Bull. Mar. Sci. (Berl.) 19(3):510-549. 

Fanning, K.A. and L.M. Bell. 1985. Nutrients in Tampa Bay. Pp. 
109-129, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. Whitman, Jr. 
(eds.) Proceedings, Tampa Bay Area Scientific Information Symposium [May 
1982]. Burgess Publishing Co., Minneapolis, MN. Available from Tampa 
BASIS, P.0. Box 290197, Tampa, FL 33687. 


108 



Federal Water Pollution Control Administration. 1969. Problems and 
managment of water quality in Hillsborough Bay, Florida. Washington, DC. 

86 pp. 

Finucane, J.H. 1966. Faunal production project. Pp. 18-22 in Report of 
the Bureau of Commercial Fisheries Biological Station, St. Petersburg 
Beach, Florida, fiscal year 1965. U.S. Fish Wildl. Serv. Circ. 242. 

Flint, R.W. 1985. Long-term estuarine variability and associated 
biological response. Estuaries 8:158-169. 

Fry, B. 1984. 13C:12C ratios and trophic importance of algae in Florida 
Syringodium filiforme seagrass meadows. Mar. Biol. 79(1):11-19. 

Garrity, R.D., N. McCann and J. Murdoch. 1985. A review of the 
environmental impacts of municipal services in Tampa. Pp. 526-550, In: 
S.F. Treat, J.L. Simon, R.R. Lewis and R.L. Whitman, Jr. (eds.) 
Proceedings, Tampa Bay Area Scientific Information Symposium [May 1982]. 
Burgess Publishing Co., Minneapolis, MN. Available from Tampa BASIS, 
P.0. Box 290197, Tampa, FL 33687. 

Gilmore, R.G., C.J. Donohoe and D.W. Cooke. 1983. Observations on the 
distribution and biology of east-central Florida populations of the 
common snook, Centropomus undecimal is (Block). Fla. Sci. (Spec. Issue, 
FIRST Sympos.) 46(3/4)313-336. 

Guist, G.G. and H.J. Humm. 1976. Effects of sewage effluent on growth 
of Ulva lactuca. Fla. Sci. 39(4):267-271. 

Hoffman, W.E. and C.J. Dawes. 1980. Photosynthetic rates and primary 
production by two Florida benthic red algal species from a salt marsh and 
a mangrove community. Bull. Mar. Sci. 30:358-364. 

Hoffman, W.E., M.J. Durako and R.R. Lewis. 1985. Habitat restoration in 
Tampa Bay. Pp. 636-657, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 
Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Hopkins, T.L. 1977. Zooplankton distribution in surface waters of Tampa 
Bay, Florida. Bull. Mar. Sci. 27:467-478. 

Hutchinson, C.B. 1983. Assessment of the interconnection between Tampa 
Bay and the Floridan Aquifer, Florida. U.S. Geol. Surv. Water Resour. 
Invest. 82-54. 

Johansson, J.O., K.A. Steidinger and D.C. Carpenter. 1985. Primary 
production in Tampa Bay: a review. Pp. 279-298, In: S.F. Treat, J.L. 
Simon, R.R. Lewis and R.L. Whitman, Jr. (eds.) Proceedings, Tampa Bay 
Area Scientific Information Symposium [May 1982]. Burgess Publishing 
Co., Minneapolis, MN. Available from Tampa BASIS, P.0. Box 290197, 
Tampa, FL 33687. 


109 






Lewis, R.R. 1983. Impact of oil spills on mangrove forests. Pp. 
171-183, In: H.J. Teas (ed.) Biology and Ecology of Mangroves. Tasks for 
Vegetation Science 8. Dr. W. Junk, The Hague. 188 pp. 

Lewis, R.R., J.M. Carlton and R. Lombardo. 1984. Algal consumption by 
the manatee ( Trichechus manatus L.) in Tampa Bay, Florida. Fla. Sci. 
47(3):189-190. 

Lewis, R.R., M.J. Durako, M.D. Moffler and R.C. Phillips. 1985. 
Seagrass meadows of Tampa Bay: a review. Pp. 210-246, In: S.F. Treat, 
J.L. Simon, R.R. Lewis and R.L. Whitman, Jr. (eds.) Proceedings, Tampa 
Bay Area Scientific Information Symposium [May 1982]. Burgess Publishing 
Co., Minneapolis, MN. Available from Tampa BASIS, P.0. Box 290197, 
Tampa, FL 33687. 

Lewis, R.R. and E.D. Estevez. In press. Tampa Bay: an estuarine 
community profile. U.S. Fish Wildl. Serv., Office of Biological 
Services. 

Lewis, R.R. and R.C. Phillips. 1980. Seagrass mapping project, 
Hillsborough County, Florida. Report to Tampa Port Authority. 30 pp. + 
maps. 

Livingston, R.J. 1984. Trophic response of fishes to habitat 
variability in coastal seagrass ecosystems. Ecology 65(4)1258-1275. 

Lombardo, R. and R.R. Lewis. 1985. A review of commercial fisheries 
data. Pp. 614-634, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 
Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Moe, M.A., Jr. and G.T. Martin. 1965. Fishes taken in monthly trawl 
samples offshore of Pinellas County, Florida, with new additions to the 
fish fauna of the Tampa Bay area. Tulane Stud. Zool. 12(4):129-151. 

Odum, W.E. and E.J. Heald. 1972. Trophic analyses of an estuarine 
mangrove community. Bull. Mar. Sci. 22(3):671-738. 

Odum, W.E., C.C. Mclvor and T.J. Smith III. 1982. The ecology of the 
mangroves of south Florida: a community profile. U.S. Fish Wildl. Serv. 
FWS/0BS-81/24. 144 pp. 

Officer, C.B., R.B. Biggs, J.C. Taft, L.E. Cronin, M.A. Tyler and W.A. 
Boynton. 1984. Chesapeake Bay anoxia: origin, development and 
significance. Science 223:22-27. 

Orth, R.J. and K.A. Moore. 1983. Submerged vascular plants: techniques 
for analyzing their distribution and abundance. Mar. Tech. Soc. J. 
17(2):38-52. 


110 




Orth, R.J. and J. Van Montfrans. 1984. Epiphyte-seagrass relationships 
with an emphasis on the role of micrograzing: a review. Aq. Bot. 
18:43-69. 


Patton, G.W. 1980. Studies of the West Indian manatee ( Trichechus 

manatus ) in Tampa Bay, Florida. Mote Mar. Lab., Sarasota, Fla. 

Paul, R.T. and G.E. Woolfenden. 1985. Current status and recent trends 
in bird populations of Tampa Bay. Pp. 426-447, In: S.F. Treat, J.L. 
Simon, R.R. Lewis and R.L. Whitman, Jr. (eds.) Proceedings, Tampa Bay 
Area Scientific Information Symposium [May 1982]. Burgess Publishing 
Co., Minneapolis, MN. Available from Tampa BASIS, P.0. Box 290197, 
Tampa, FL 33687. 

Reynolds, J.E. and G.W. Patton. 1985. Marine mammals, reptiles and 
amphibians of Tampa Bay and adjacent coastal waters of the Gulf of 
Mexico. Pp. 448-459, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 
Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Ross, B.E., M.A. Ross and P.D. Jerkins. 1984. Wasteload allocation 
study, Tampa Bay, Florida. Florida Dept, of Environmental Regulation, 
Tallahassee. Vol. 1-4. 

Schreiber, R.W. and E.A. Schreiber. 1983. Use of age classes in 
monitoring population stability of brown pelicans. J. Wildl. Mgt. 
47:105-111. 

Santos, S.L. and J.L. Simon. 1980. Marine soft-bottom community 
establishment following annual defaunation: larval or adult recruitment? 
Mar. Ecol. Prog. Ser. 2:235-241. 

Simon, J.L. 1974. Tampa Bay estuarine system - a synopsis. Fla. Sci. 
37(4):217-245. 

Simon, J.L. and S.K. Mahadevan. 1985. Benthic invertebrates of Tampa 
Bay [abst.]. P. 384, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 
Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Springer, V.G. and A.J. McEarlean. 1961. Notes on and additions to the 
fish fauna of the Tampa Bay area. Copeia 4:480-482. 

Springer, V.G. and K.D. Woodburn. 1960. An ecological study of the 
fishes of the Tampa Bay area. Fla. State Board Conserv. Mar. Lab. Prof. 
Pap. Ser. 1. 104 pp. 

Steidinger, K.A. and W.E. Gardiner. 1985. Phytoplankton of Tampa Bay: 
a review. Pp. 147-183, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 


111 




Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Taylor, J.L. 1973. Biological studies and inventory - Tampa Harbor, 
Florida, Project. Taylor Biological Co., Jacksonville, FL. 181 pp. + 
app. 

Taylor, J.L., J.R. Hall and C.H. Saloman. 1970. Mollusks and benthic 

environments in Hillsborough Bay, Florida. U.S. Fish Wildl. Serv. Fish. 

Bull. 68)2:191-202. 

Twilley, R.R., W.M. Kemp, K.W. Staver, J.C. Stevenson and W.R. Boynton. 
1985. Nutrient enrichment of estuarine submersed vascular plant 

communities. I. Algal growth and effects on production of plants and 
associated communities. 

Van Montfrans, J., R.J. Orth and S.A. Vay. 1982. Preliminary studies of 

grazing by Bittium varium on eelgrass periphyton. Aq. Bot. 14:75-89. 

Virnstein, R.W., P.S. Mikkelsen, K.D. Cairns and M.A. Capone. 1983. 
Seagrass beds versus sand bottoms: the trophic importance of their 
associated benthic invertebrates. Fla. Sci. 46(3/4):363-381. 

Weiss, W.R. and T.D. Phillips. 1985. Meroplankton and the Tampa Bay 
system. Pp. 345-358, In: S.F. Treat, J.L. Simon, R.R. Lewis and R.L. 
Whitman, Jr. (eds.) Proceedings, Tampa Bay Area Scientific Information 
Symposium [May 1982]. Burgess Publishing Co., Minneapolis, MN. 
Available from Tampa BASIS, P.0. Box 290197, Tampa, FL 33687. 

Williamson, G.B. and E.C. Mosura. 1979. Cold stress on mangroves in 

Tampa Bay, Florida. Tampa Port Authority. 63 pp. 

Windsor, J.G., Jr. 1985. Nationwide review of oxygen depletion and 
eutrophication in estuarine and coastal waters: Florida region. Project 
report, Brookhaven National Laboratory, Upton, NY. 177 pp. 

Woolfenden, G.E. and R.W. Schreiber. 1973. The common birds of the 

saline habitats of the eastern Gulf of Mexico: their distribution, 

seasonal status, and breeding ecology. Pp. 111J-1 through 111J-22, In: 

J.I. Jones, R.E. Ring, M.L. Rinkel and R.E. Smith (eds.), A summary of 

knowledge of the eastern Gulf of Mexico 1973. Fla. State University 
System of Oceanography, St. Petersburg. 

Zieman, J.C. 1982. The ecology of the seagrasses of south Florida: a 
community profile. U.S. Fish Wildl. Serv. FWS/OBS-82/85. 158 pp. 

Zimmerman, R., R. Gibson and J. Harrington. 1979. Herbivory and 
detritivory among gammaridean amphipods from a Florida seagrass 
community. Mar. Biol. (Berl.) 54:41-47. 


112 


HABITAT TRENDS AND FISHERIES IN TAMPA AND SARASOTA BAYS 


Ken Haddad 

Florida Department of Natural Resources 
St. Petersburg, Florida 


Fisheries are an important result of the complex biological web of 
Tampa and Sarasota Bays. Habitat plays an important critical role in 
defining the success of any given species within a system. Habitat refers 
to the specific structural, physical, and chemical environment in which 
an organism lives. This paper will focus on several components of the 
estuary considered important to the juvenile populations of commercial 
and recreational fishery species in Tampa and Sarasota Bays. The 
discussion on fisheries will provide only an overview of the actual 
industry and highlight some relatively new programs that will have a 
long-term influence on fisheries management in the bays. General 
references to Tampa Bay imply the inclusion of Sarasota Bay unless 
otherwise stated. 


HABITAT TRENDS 


Fisheries habitat includes mangrove, saltmarsh, seagrass meadow, 
intertidal mudflat, and unvegetated subtidal bottom communities. An 
integral and encompassing habitat component that influences the 
distribution of other components is the water column. Other less 
extensive, specific habitats of the Tampa Bay system contribute to the 
fishery, but they will not be detailed here. Figure 1 defines the 
boundaries of the quantitative analyses for habitat distribution and 
trends. The total estuarine area for this region is 124,155 hectares 
(ha, 1 ha=2.47 acres). 

Mangroves cover approximately 8,036 ha, or 7% of the bay estuarine 
environment. Although Tampa Bay is near the northern limit of their 
distribution, mangroves remain an important component of the intertidal 
system. The aerial root systems provide a substratum for algal and 
invertebrate attachment and serve as a structural and protective habitat 
for juvenile fish, crustaceans, and shellfish. Leaf litter can also be 
important, forming the basis of a mangrove-detritus food web and 
providing a food supply to many organisms and ultimately the fishery. 
Mangroves also stabilize sediment and can be a nutrient and sediment trap 
for upland runoff. 

Saltmarshes cover approximately 1,432 ha, or 1% of the bay 
estuarine environment. In Tampa Bay they generally serve as intertidal 
transition zones between mangroves and the freshwater marsh systems. 
Marshes also grow in mangrove areas damaged by occasional freezes (Lewis, 
this report). Like mangroves, saltmarshes provide a concentration of 
high-quality food for estuarine animals in addition to a protective 


113 






Figure 1. Boundaries for the quantitative analysis of habitat 
distribution and trends in the Tampa Bay Region. 


114 





environment for early life stages. Saltmarshes are also a fundamental 
part of nutrient cycles, long-term accumulators of pollution, short-term 
pollution buffers, and inhibitors of erosion. 

Seagrass Meadows cover approximately 12,968 ha, or 10% of the bay 
system. They are the dominant vegetative cover in the bay and are 
critically important to productivity of the bay system. Seagrass meadows 
provide a direct food source to herbivores, such as sea turtles and 
manatees, and to numerous detritivores. Because this habitat is subtidal 
and extensive in distribution, it provides a constant and expansive 
structural shelter for fish, shellfish, and crustaceans important to the 
fishery. In addition, the complex food web and tremendous organism 
diversity and quantity provide a major food source to all stages of 
fishery species in the bay. Seagrass meadows also stabilize sediments 
and prevent erosion. They improve water quality by removing nutrients 
and by providing a baffle effect on waves and currents, which causes 
settling of suspended particulates in the water column. Macroalgae, in 
either drift or attached forms, are often associated with seagrass 
meadows and other communities of the estuary. The algae are a more 
readily digestible food source than seagrass and appear to be important 
to the ecology of the estuary. 

Mudfl ats (sandbars, sandflats, flats) cover approximately 
9,389 ha, or 8% of the bay bottom. They are "unvegetated" sites that 
become exposed at low tide. During the day they serve as primary feeding 
grounds for wading and shore birds. At night, fish, crabs, and shrimp 
become major consumers. Production in a mudflat is driven by smaller 
algae, such as dinoflagel1ates, diatoms, and blue-greens; macrophytic 
algae have a lesser role. Flats do not provide a protective structural 
component except to burrowers. A special type of flat found in Tampa Bay 
is the saltbarren (saltern), a transitional area between mangrove- 
saltmarsh and uplands. Although a harsh habitat, saltbarrens are 
important for bird populations, and growing evidence exists that they 
support fisheries species during irregular flooding. Saltbarrens host a 
variety of vegetation from stressed mangroves to lush succulents. 

Unvegetated subtidal bottom comprises 92,334 ha, or 74% of the 
estuary. For this discussion, this area also includes artificial reefs, 
natural rock reefs, algal communities, sand, mud, and others. This 
habitat type is a major component of the system, as in most estuaries, 
and although extremely important for overall bay production, its extent 
serves to emphasize the importance of the relatively lesser amounts of 
structural, vegetative cover on the periphery of the bay. 

Depending on the tides, the water column , overlies part or all of 
the estuarine habitat. The chemical, physical, and biological 
composition of the water column influences all aspects of the estuary. 
Phytoplankton are the primary producers and not limited to shallow areas 
or shorelines (as are seagrasses, mangroves, and saltmarshes). 
Phytoplankton exist as readily digestible food for consumers and are 
essential components in the food chain that supports larval stages of the 
fishery. An abnormal abundance of phytoplankton occurs in the Tampa Bay 


115 






region as a result of an overabundance of dissolved nutrients. This 
process of eutrophication can have serious implications for the quality 
of production in the bay. 

Through a cooperative study, the U.S. Fish and Wildlife Service 
(USFWS) and the Florida Department of Natural Resources (FDNR) estimated 
habitat changes in the Tampa Bay area from the 1950’s to 1982. The data, 
housed in digital form on the DNR Marine Resource Geographic Information 
System (MRGIS) are photo-interpreted aerial photographs that have been 
computer digitized in a 1:24000 scale using the National Wetlands 
Inventory standard classification system. Over 600 separate categories 
are detailed in this hierarchical classification for the Tampa Bay 
region. Two 7.5-minute USGS topographic quadrangles (approximately 
36,000 ha, northwest and southwest portion of Figure 1) have been 
interpreted and digitized into the MRGIS in addition to the data 
developed in conjunction with USFWS. The data have been synthesized on 
the MRGIS into general categories for ease of discussion (Table 1). 


Table 1. Summary of major habitat trends, in hectares, for the Tampa Bay 
region. 


Habitat 

1950 

1982 

Percent Chanqe 

Mangrove 

8,629 

8,032 

- 7 

Saltmarsh 

2,063 

1,432 

- 30 

Seagrass 

25,801 

12,968 

- 50 

Mudflats 

6,812 

9,389 

+ 37 

Freshwater wetland 

18,335 

14,440 

- 21 

Agriculture 

25,347 

45,193 

+ 78 

Range/forest 

124,630 

42,997 

- 65 

Urban 

32,730 

95,586 

+192 


Lewis et al. (1985) estimated that 44% of the saltmarsh and 
mangrove and 81% of the seagrass meadows have been lost in Tampa Bay 
since the late 1800’s. The recent calculations (Table 1) are not readily 
comparable because of differences in time, methodology, vegetation 
classification, and aerial coverage. However, the results confirm that 
significant losses of habitat have occurred. Perhaps the most 
significant deviation from other published results is the seemingly small 
loss of mangroves (7%) in the bay. This is an artifact of the USFWS 
classification system which underestimates change for this particular 
category and is being addressed in the MRGIS database. 

Significant loss of fishery habitat has occurred in the Tampa Bay 
area. Loss of marsh and mangrove has been the result of dredge and fill 
activities. Dredge and fill has caused direct loss of seagrasses and 
indirect impacts have been hypothesized, primarily from changes in water 
quality which preclude seagrass growth. Dredge and fill activities are 


116 





now under strict control; although permitted dredging continues, 
protective measures exist to minimize loss that is not "for public 
benefit". Water quality is considered the primary and continuing limit 
to seagrass distribution in the bay. Loss of seagrass has generally 
occurred throughout the bay, but the most significant losses have 
occurred in Boca Ciega Bay and the upper portion of Tampa Bay. In Boca 
Ciega Bay, shallow seagrass meadows were dredged into massive fill areas 
for residential and commercial development. Simon (1974), citing other 
researchers, indicates that loss of Boca Ciega Bay bottom destroyed a 
standing crop of 1,133 metric tons of seagrass and in annual production; 
25,841 metric tons of seagrass; 73 metric tons of fisheries products; and 
1,091 metric tons of associated infauna. In 1968, this translated to an 
estimated value of $160/hectare/year loss, or $1.4 million, annually. 
Simon (1974) estimated a loss in natural investment by 1974, if 
capitalized at 6%, of $23 million. Although these values are opinionated 
estimates, the point to understand is that these are substantial economic 
losses. 


Loss of seagrass in upper Tampa Bay has been caused partially by 
dredge and fill, but the majority has not been due to direct mechanical 
destruction. Figure 2 depicts seagrass loss since 1950. In Hillsborough 
Bay (eastern extension of the upper bay), the loss is 90%. Changes in 
water quality suspected as the causative factors can be attributed to: 1) 
loss of range/forest and freshwater and saltwater wetlands,which act as 
filtering systems for runoff; 2) increases in agricultural area, which 
may increase sedimentation and suspended particles in the water; 3) 
intense urbanization and industrialization, which generate wastewater and 
stormwater disposal problems; and 4) dredging, which causes long-term 
release of fine sediments into the bay environment. With such large 
increases in urban and agricultural development (see Table 1) and 
decreases in those habitats that cleanse and buffer the bay, we can 
expect imbalances and changes to occur within the system as a whole. 

The overall importance of the seagrass community to the region 
cannot be overstated. For perspective, the Chesapeake Bay estuary 
encompasses 3,237 sq. mi. and has 75 sq. mi. of seagrass (2% coverage), 
whereas the Tampa Bay region encompasses 479 sq. mi. and has 50 sq. mi. 
of seagrass (10% coverage). A major issue in Chesapeake Bay has been the 
importance of the seagrass meadows to the overall production in the bay. 
It is readily apparent that this should be a major issue for Tampa Bay. 


FISHERIES 


The Tampa Bay region has historically been a highly productive 
source of consumable fish and shellfish. Indian populations used the bay 
for food and tools. During the 19th century, the bay was a commercial 
fishing area for boats from as far away as New England (Pizzo, 1968; cf. 
Lombardo and Lewis, 1985). The first known fishery lost in the bay was 
the Atlantic sturgeon, with 5,000 lb. landed in 1867 and 6,500 lbs landed 
in 1868. Sturgeon all but disappeared in 1869, probably due to fishing 


117 



U L 39HJ8S S 305'3:0 



LEGEND 



Land 

Seagrass (1982) 

Seagrass-present in 1950 
but absent in 1982 


IK 3SS005 S.aOKfi'SO 


Figure 2. Seagrass loss in upper Tampa Bay and Hillsborough Bay. 


118 




























pressure and poor recruitment; they no longer inhabit the bay. The area 
remains a fishing center, but fishing is not the primary water-dependent 
industry. Two counties in the Tampa Bay region --Pinellas and 
Hillsborough-- ranked 2nd and 6th, respectively, in value of Florida 
landings in 1976 (Mathis et al., 1979), confirming the importance of the 
industry even to the present. The 1986 dockside value of the fishery to 
the region is presented in Table 2 as estimates; the prices used to 
calculate the values are based on statewide averages and do not reflect 
local variations. 


Table 2. 1986 fisheries landing for the Tampa Bay region including the 

number of trips made by the fishermen, pounds landed, and value 
of the fishery at dockside (Kennedy, pers. comm.). 


Countv Landed 

Trios 

Pounds 

Dockside Value $ 

Pinellas 

32,549 

10,658,222 

$14,275,594 

Hillsborough 

8,463 

8,662,909 

5,293,494 

Manatee 

28,412 

15,395,044 

4,938,522 

Sarasota 

5.799 

659,400 

356.228 

TOTAL: 

75,223 

35,375,575 

$24,863,838 

Commercial 

landings have traditionally been used 

to monitor trends 


in the fishing industry and economic value. Commercial landings data 
have historically been collected by the National Marine Fisheries Service 
(NMFS) and were originally designed to monitor the value of the fishery 
on a national scale. Landings data have little additional validity other 
than to observe possible trends in the fishery. NMFS landings data 
cannot provide the number of man-hours to catch a fish (catch per unit 
effort), the recreational catch, or where the fish were caught. These 
put severe limitations on the interpretation of the data, i.e., whether a 
decline is due to fewer fish, fewer fishermen, low dockside prices, or 
inclement weather. 

Enhanced approaches to fisheries management have been instituted 
at the state level which will have a positive impact on fisheries 
management in Tampa Bay. The 1983 Florida Legislature created the Marine 
Fisheries Information System to gather the types of fisheries data 
necessary for management and research. FDNR expanded the NMFS commercial 
landing data collection to create a marine fisheries trip ticket. 
Florida law requires that anyone wishing to sell their catch of saltwater 
products must have a valid Saltwater Product License and that licensed 
wholesale seafood dealers must maintain records of each sale on a coded 
trip ticket. The data collected are both mandatory and voluntary. The 
mandatory information includes time fished, county landed, species sold, 
and number of pounds of each species caught. The voluntary information 
requested includes area fished, depth where caught, number of traps 


119 










pul 1ed/days since last pulled, and price per pound. Voluntary reporting 
has been used for the latter information, because it was felt that these 
specific types of information would be more reliably reported. Voluntary 
information has been used to estimate total landing for an area by 
statistically extrapolating the percent of voluntary "area fished" 
reports to the landings that did not have this information. Catch per 
unit effort by area can be determined by comparing the number of trips 
reported and the time fished with the pounds of each species caught. 

The estuarine species listed in Table 3 are indicative of those 
produced and caught in Tampa Bay. By using the trip ticket information, 
we can specifically target the bay landings. For example, bait shrimp 
landings in pounds can be extrapolated to 31,619,800 live individuals. 
By using "area caught" information (not shown), we can estimate that only 
about 5,000,000 of those shrimp were caught in Tampa and Sarasota Bays; 
the remainder were caught north and south of the bay. Eight hundred 
trips were needed to catch the 5,000,000 shrimp, or 6,250 shrimp/trip 
worth about 150 dollars to the shrimper. 


Table 3. Some typical species caught in the Tampa Bay region in 1986. 


Species 

Trios 

Pounds 

Dockside Value $ 

Bait shrimp 

4,341 

316,198 

$ 692,473 

Blue crabs 

1,852 

198,025 

74,690 

Cl ams 

54 

5,219 

24,894 

Menhaden 

328 

5,106,083 

255,304 

Mullet 

12,748 

6,842,456 

2,253,528 

Sheepshead 

4,101 

100,193 

33,063 

Spotted seatrout 

7,037 

175,432 

171,923 

Oysters 

1 

103 

31 


The majority of the remaining species in Table 3 were caught in 
the bay region. The major fishery in pounds and value is mullet. An 

Asian market for mullet roe (up to $30/1 b retail) was developed in the 

1970’s and has influenced the value of this fishery tremendously 

(Figure 3). Fishing pressure has also increased, and research is 
currently being conducted on mullet populations. 

Clam and oyster landings are very low in this area, primarily 
because only 15-20% of the potential shellfish areas are approved for 
harvest. The Department of Natural Resources has been systematically 
closing portions of the bay to shellfishing, because these areas do not 
meet state and federal water quality standards for shellfishing. Old 
Tampa Bay was permanently closed in 1979, and portions of the lower bay 
system have been temporarily closed in the 1980’s. Permanent closures 

are expected to increase with continued urban growth around the bay. 
Scallops, which require good water quality, disappeared from the bay by 


120 







TOTAL VALUE OF BLACK MULLET FISHERY 



T 

r- 


n-1-1-1-r 

<£) UO to C\J 


( 000‘000‘l x 5 


3mvA nvioi 


ro 

rr> 

& 


121 


Figure 3. Black millet fishery value in Tampa Bay, 1940-1983. 




1963 (in commercially or recreationally viable numbers) and are only 
occasionally found today. 

Menhaden are another species actively sought in the bay. The 
catch was minimal until 1985, when a controversial fishery suddenly 
developed. The recreational fishermen targeting tarpon have complained 
that tarpon no longer feed in the bay as they have in the past, because 
commercial fishermen are catching all of the baitfish, such as menhaden. 
Some research is currently funded to address the baitfish problem, which 
in reality can be accomplished only by understanding the entire 
ecosystem. 

Spotted seatrout landings further demonstrate the utility of the 
marine fisheries trip ticket information. Of the 175,000 lbs landed, 
157,000 lbs were from the bay system. Of the 7,655 trips reporting 
trout, only 278 landed more than 100 lbs, suggesting that trout are an 
incidental catch. In fact, the primary catch is mullet. Of the 278 
trips that apparently targeted seatrout, 111 trips were in January when 
trout can be concentrated in schools. 

The value of this type of information cannot be overstated. It 
provides a tool for management that has never before been available and 
does not exist elsewhere in the southeastern region of the country. 
Recreational catch records are also critically important in complementing 
the commercial fisheries statistics now being collected. Recreational 
data are currently collected by NMFS, but they do not have enough 
regional and local statistical validity to correlate with the trip ticket 
data. Unfortunately, these data remain a much needed informational 
component in the Tampa Bay region. 

Historical NMFS commercial landings can be compiled to observe 
potential trends in individual fisheries. Keeping the limitations of the 
NMFS data in mind, landings for spotted seatrout, Cvnoscion nebulosus . 
and bait shrimp, Panaeus duorarum, are presented in Figure 4. Declines 
in catch are consistent and significant and should be cause for alarm. 

Spotted seatrout have historically comprised an important 
recreational and commercial fishery in the Tampa Bay region. Scientific 
data documenting the reasons for decline in this species do not exist, 
but we can speculate based on existing knowledge of the juveniles and 
adults in the Tampa Bay system. McMichael and Peters (in preparation) 
found that seagrass meadows in Tampa Bay appear to be the primary nursery 
ground for juvenile seatrout. Seventy-eight percent of 1,379 juveniles 
collected were found in seagrass, though less than 40% of the collections 
were made in this habitat. Furthermore, commercial and recreational 
fishermen target seagrass meadows as the most likely source of adult 
spotted seatrout. Seatrout are non-migratory, spending their entire life 
cycle in a given estuary, and thus the Tampa Bay region can be assumed to 
produce and support its own population with minimal external influences. 
Although numerous factors control the spotted seatrout population, a loss 
of 50-80% of the seagrasses in Tampa Bay should affect landings. We may 
also assume that with the loss of seagrasses, the actual production 


122 






POUNDS LANDED ( x IOOO) NUMBER of INDIVIDUALS (xIOOO) 


50000- 


40000 


30000 - 


20000 - 


0000 - 



r" 


-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-i- 1 -r—r 


1950 1955 


I960 1965 

YEAR 


1970 1975 1980 


1000 - 
900 
800 -I 
700 
600- 
500- 
400 
300 
200 
100 -I 



t -1-1-1-1-1-1-1-1—i-1-1-1-1-1-1-1—i-1-1—i-1-1-1-1-1—i-1-1—i-r 

1950 1955 I960 1965 1970 1975 1980 

YEAR 


Figure 4. Landings of bait shrimp (top) and spotted seatrout (bottom) in 
Tampa Bay. 


123 







potential (carrying capacity) of this species would be reduced in the 
bay, and the seatrout population could not recover to historical levels, 
even if all fishing pressures were eliminated. 

The bait shrimp industry also relies heavily on production in 
seagrass meadows. Bait shrimp are kept alive and sold in the retail 
market to recreational fishermen. The shrimp are captured by roller- 
trawls specifically designed to work efficiently in seagrass meadow 
target areas. Unlike seatrout, adult shrimp migrate offshore to spawn, 
and the juveniles return to use the seagrasses, marshes, and mangroves as 
nursery grounds. Again, the loss of seagrass can be expected to 
influence the catch of bait shrimp and their population potential. 

The two species just described are representative of many 
commercial and recreational species caught in Tampa and Sarasota Bays. 
Over 70% of the commercial and recreational species caught in Florida 
utilize the estuaries during some portion of their lifecycles, suggesting 
that we must understand the estuary as a system in order to manage the 
fishery. Each estuary has unique characteristics that separate it from 
others that may be reflected in the fishery. For example, biologists 
have found that the primary nursery ground for red drum (redfish, 
Sciaenops ocel1atus ) in some Texas estuaries appears to be seagrass 
meadows (Holt et al., 1983), whereas Peters and McMichael (1987) 

determined that primary nursery areas in Tampa Bay are quiet backwaters 
with freshwater influences. The red drum in Texas spawn offshore; the 
Tampa Bay red drum spawn at or near the entrance to the bay. These 
findings suggest that specific studies in individual estuaries may not 
apply uniformly to other estuaries which have different physical, 
chemical, and biological characteristics. We must understand Tampa Bay 
as a system and conduct appropriate, systematic research to elucidate the 
information required for effective fisheries management. 

The landings data report only adult populations. Juvenile 
populations can be assumed to have a great influence on the size of the 
adult populations. Influences on the juvenile populations, such as 
habitat availability, climatic cycles, spawning success, species 
competition, and a myriad of other factors, should translate into the 
potential production of a fishery. Unfortunately, most fisheries 
research has not concentrated on understanding the quantifiable 
relationships within an ecosystem. Years of catch-up research must be 
conducted in order to develop population projection capabilities that 
can be effectively used in fisheries management. 

Research is being conducted in Tampa Bay to develop techniques for 
assessing juvenile populations of commercially and recreationally 
important species prior to their entry into the fishery. We expect that 
relationships between relative abundance of a juvenile population and 
commercial and recreational landings of adults will provide a tool for 
projecting the fishery in advance. The fishery can then be managed 
according to the resource available. This long-term program is linked 
with research to determine habitat carrying capacities and production 
potential. The research is being carried out with funding or cooperation 


124 




from the National Oceanic and Atmospheric Administration Office of Ocean 
and Coastal Resource Management, National Marine Fisheries Service, U.S. 
Fish and Wildlife Service, Florida Department of Environmental 
Regulation, and the Florida Department of Natural Resources. 

Only through cooperative federal, state, and local programs and 
research can the fishery in Tampa and Sarasota Bays be understood and 
managed effectively. For further information on fisheries programs, 
contact Frank S. Kennedy, FDNR Bureau of Marine Research, 100 8th Ave. 
SE, St. Petersburg, FL 33701. 


RESTORATION 


One logical approach to revitalizing the bay and ultimately the 
fishery is to enhance the existing habitat. Restoration projects are not 
new to the Tampa Bay region. They have generally been coupled with 
mitigation of permitted habitat destruction or small independently 
sponsored projects. No overall systematic approach has been taken to 
monitor and evaluate the results of restoration. 

In 1985, the Department of Natural Resources developed a 
legislatively-mandated Marine Habitat Restoration and Research Program, 
focusing on the restoration of natural vegetative components of marine 
fisheries habitat (saltmarsh, mangrove, and seagrass). The program was 
facilitated by commercial mullet fishermen who sponsored legislation 
requiring a $300 per annum County Gill-Net License. The legislation 
targeted the Tampa Bay region and overcame the major obstacle to 
implementing a marine habitat restoration program -- lack of funding. To 
date, four counties in Florida have adopted this legislation, providing 
the local initiative critical to the recovery of the bay: Pinellas 
(1983); Manatee (1984); Hillsborough (1987); and Pasco (1984). All of 
these counties are in the Tampa Bay region, and the first three encompass 
Tampa and Sarasota Bays. Revenues over $100,000 per year are 
administered by the Florida Department of Natural Resources and are 
legislatively mandated to be used for "marine habitat restoration and 
research". In addition, local state legislators have provided seed money 
for specific restoration research on seagrasses, but these funds are not 
on a continuing basis, such as the county net bill funds. 

The Tampa Bay restoration projects have been designed to 
facilitate significant contributions toward understanding the dynamics of 
habitat restoration and resource recovery. Without valid project design, 
results from one project cannot be transferred to another, a factor often 
overlooked by those seeking comprehensive planning solutions to complex 
environmental problems. 

Activities in 1986-87 have involved transplanting of saltmarsh, 
mangroves, and seagrass at several sites in the bay. Some experimental 
plots have been monitored only for survival and growth, whereas other 
experiment sites are intensively monitored for planting unit survival and 


125 



spread, water column chemistry (seagrass), and faunal utilization. 
Monitoring will continue at experimental sites for a minimum of three 
years while site selection continues for future saltmarsh and seagrass 
plantings. 

Success is not guaranteed in restoring natural vegetation. 
Factors controlling planting success may be site specific and vary with 
planting stock sources and handling. Survival of planting units thus far 
have ranged from zero to 100%. Seagrass restoration is proving to be the 
most difficult to accomplish, as losses have been extensive and appear to 
be related to changes in water quality. Until basic water quality 
relationships with seagrass are understood and addressed, large scale 
restoration cannot be accomplished. Unfortunately, funds are more easily 
made available for replanting, and the needed basic research is often 
overlooked. 

The principal interest of this program is in restoration of the 
complex functions of marine fisheries habitat, which presumably begins 
with revegetation. Utilization of those habitats created by fisheries 
organisms, although costly to assess, will provide a perspective on the 
value of created vs. natural environs. Before large-scale restoration of 
the Tampa Bay area can begin, planting techniques, survival of plantings, 
and habitat contributions must be understood. This information is 
essential to the long-term management of our coastal resources and marine 
fisheries. The FDNR is being assisted in this work by the NMFS; Mote 
Marine Laboratory; Pinellas, Hillsborough, Manatee, and Pasco Counties; 
Pinellas Marine Institute; Mangrove Systems, Inc.; and other contracted 
and volunteer organizations. The Tampa Bay region has provided the 
initiative and funding for this effort and demonstrates that difficult 
tasks may be accomplished by local, state, and federal interactions. For 
more information on restoration research, contact Alan Huff, FDNR Bureau 
of Marine Research, 100 8th Avenue SE, St. Petersburg, FL 33701. 


STOCK ENHANCEMENT 


Stock enhancement is another approach to fisheries restoration. 
The practice entails hatching, rearing, and releasing fish into the 
natural environment to augment or enhance target species populations. 
Stocking of freshwater fishes into lakes, reservoirs, and streams for a 
management tool and/or for a put-and-take fishery is common. Stocking of 
fingerling marine fish into estuaries is a relatively untried concept. 
Stock enhancement in Florida is currently in pilot stages without 
production hatcheries. The principal hatchery research participants are 
the University of Miami Experimental Fish Hatchery, Miami; Mote Marine 
Laboratory, Sarasota; Harbor Branch Foundation, Indrio; and FDNR Bureau 
of Marine Research, St. Petersburg. The state is constructing an 
experimental hatchery in Manatee County adjacent to Tampa Bay, on 
property provided by the Manatee Port Authority. This facility will be 
the center for research on hatching, rearing, and stocking of red drum, 
snook, and other species. 


126 



Success in stocking marine fishes depends on species chosen, size 
of fish released (smaller sizes are more susceptible to predation and 
environmental stress), and habitat carrying capacity (how many juveniles 
or adults can be supported per acre regardless of the number of fish 
released). Also, from a hatchery perspective, bio-energenics, growth, 
metabolism, osmotic/ionic systems, reproductive physiology, feeding 
dynamics, behavior, and genetics have not been thoroughly investigated 
(if at all) for most estuarine species. 

There are many questions that need to be answered before full- 
scale stocking, if feasible, can be accomplished. The problems are 
multi-disciplinary and will require a myriad of information to accomplish 
an environmentally sound enhancement program. The fisheries and habitat 
research already discussed will greatly enhance the information base of 
the stock enhancement program. The Tampa Bay region is fortunate to have 
this program centered here because of the existing related programs and 
the demonstrated ability of the scientific and management community to 
work together. For further information on stock enhancement research, 
contact Daniel Roberts, FDNR Bureau of Marine Research, 100 8th Avenue 
SE, St. Petersburg, FL 33701. 


SUMMARY 


I have briefly addressed fisheries habitat concerns and trends, 
fisheries management and research needs, habitat restoration, and stock 
enhancement in Tampa and Sarasota Bays. The complexities of the research 
have been presented only as an overview. It is important to recognize 
the cooperative spirit demonstrated by researchers and managers in 
addressing the problems within this estuary. 

Much of the habitat necessary for the maintenance of quality 
biological production in the bay has been altered. New approaches to 
fisheries management are being implemented, which should provide enhanced 
techniques for quantitatively understanding the fishery populations in 
the bay. Restoration and stock enhancement programs may help to increase 
the quality of production in the bay. Funding continues to be a prime 
concern for research and management, but, because of the spirit of 
cooperation in the bay area, much has been accomplished with minimal 
dollars. Most programs are minimally funded and need to be put on 
accelerated schedules. Unless long-term committed sources of funding are 
directed to the bay area, little improvement in the bay system can be 
expected in the next decade. 


127 



LITERATURE CITED 


Holt, S., C. Kitting, and C. Arnold. 1983. Distribution of young red 
drum among different seagrass meadows. Trans. Am. Fish. Soc. 

112:267-271. 

Lewis, R.R., III, M.J. Durako, M.D. Moffler, and R.C. Phillips. 1985. 
Seagrass meadows of Tampa Bay. pp. 210-246, In: S. Treat, J. Simon, R. 
Lewis, III, and R. Whitman, Jr., Proceedings Tampa Bay Area Scientific 
Information Symposium. Fla. SeaGrant Rept. No. 65. 

Lombardo, R. and R. Lewis, III. 1985. A review of commercial fisheries 
data: Tampa Bay, Florida, pp. 614-634. In: S. Treat, J. Simon, R. 
Lewis, III, and R. Whitman, Jr. Proceedings Tampa Bay Area Scientific 
Information Symposium. Fla. SeaGrant Rept. No. 65. 

Mathis, K., J. Cato, R. Degner, P. Landrum, and F. Prochaska. 1979. 
Commercial fishing activity and facility needs in Florida, Hillsborough, 
Manatee, Pasco, Pinellas, and Sarasota Counties. P. 1-119. A Report to 
Gulf and South Atlantic Fisheries Foundation, Inc. and Florida SeaGrant. 

McMichael, R., Jr. and K. Peters. (in prep.) Early life history of 
Cvnoscion nebulosus (Pisces: Sciaenidae) in Tampa Bay, Florida. Fla. 
Dept. Nat. Resour. 

Peters, K. and R. McMichael, Jr. 1987. Early life history of the red 
drum, Sciaenops ocellatus (Pisces: Sciaenidae), in Tampa Bay, Florida. 
Estuaries 10(2):92-107. 

Simon, J.L. 1974. Tampa Bay estuarine system -- a synopsis. Fla. Sci. 
37(4):217-214. 


128 







SURFACE SEDIMENTS AND THEIR RELATIONSHIP 
TO WATER QUALITY IN HILLSBOROUGH BAY, 

A HIGHLY IMPACTED SUBDIVISION OF TAMPA BAY, FLORIDA 


J.O.R. Johansson and A.P. Squires, 

City of Tampa, Bay Study Group, Dept, of Sanitary Sewers 
Tampa, Florida 


INTRODUCTION 


Hillsborough Bay is the subdivision of Tampa Bay that has received 
the heaviest industrial and municipal impacts associated with the recent 
urbanization of the Tampa Bay area. Eutrophication of bay waters caused 
by urban runoff, municipal sewage and industrial discharges, may have 
contributed to a large area of muddy high organic sediments in 
Hillsborough Bay. The upper 20cm of the sediment layer, with its 
associated biota, is an important link in the coupling between the 
benthic and pelagic communities in this shallow estuarine system. A 
eutrophic system like Hillsborough Bay supports a large crop of primary 
producers, mostly phytoplankton, which produce more organic matter than 
can be utilized by the primary consumers. Surplus organic matter and 
waste material from consumers settle to the bottom creating sediments of 
high organic content. Effluents and runoff contribute additional organic 
matter to natural background levels. Organic matter in the sediment is 
mineralized and nutrients are released to the water column where they 
become available for planktonic primary production. The metabolic 
processes associated with the benthos create an oxygen demand which may 
reduce oxygen in the overlying waters. Reduced oxygen concentrations can 
have a drastic impact on the estuarine community structure through large 
scale die-offs of the benthic and pelagic fauna. Benthic nutrient 
regeneration and the related process of dentrification are important in 
the recycling and availability of nutrients in estuaries. In Hillsborough 
Bay, however, few specifics are known of rates and pathways of these 
important links between the benthic and pelagic systems. 

This paper will summarize the composition of surface sediment and 
sediment oxygen demand rates in Hillsborough Bay. Also, a first attempt 
is made to relate the nutrients released from these sediments to the 
phytoplankton, the dominant primary producers of the bay. Much more work 
is needed to understand better how the sediments and their biota affect 
water quality in Hillsborough Bay. 


TAMPA AND HILLSBOROUGH BAY SURFACE SEDIMENT STUDIES 


In Tampa Bay, including Hillsborough Bay, several studies of 
surface sediment composition and distribution have been conducted since 
the 1950’s. 


129 





Goode!1 and Gorsline (1961) analyzed surface sediments for grain 
size, carbonates and organic carbon from all major areas of Tampa Bay 
including approximately 30 stations in Hillsborough Bay. They concluded 
that Tampa Bay sediments are a mixture of eroded quartz sands from 
Pleistocene terrace deposits and carbonates from mollusk shell fragments 
produced within the system. The present sediment distribution is 
attributed to tide generated currents. In general, sediment grain size 
increases toward the mouth of Tampa Bay and fine high organic material is 
found in the upper reaches of Hillsborough Bay and isolated areas of Old 
Tampa Bay. 

The surface sediments of Hillsborough Bay were studied intensively 
in 1968 by the Federal Water Pollution Control Administration (FWPCA 
1969). This study was conducted in cooperation with local authorities to 
suggest ways to improve the poor water quality of Hillsborough Bay. 
Ninety-five surface sediment samples throughout Hillsborough Bay were 
collected and analyzed for organic carbon, nitrogen and phosphate. A 
large area of the bay bottom (16%) contained sediments with a high 
organic carbon content of at least 3% of sediment dry weight. Highest 
organic carbon sediment concentrations were associated with discharge 
points from sewage treatment plants, river mouths, and areas deeper than 
ten feet with weak tidal currents. The most important sources of high 
organic mud were thought to be the Hillsborough and Alafia Rivers, the 
Hooker’s Point primary treatment plant, and the decomposition of settled 
phytoplankton. The nitrogen content of the sediments followed the 
distribution pattern of organic carbon, while sediment phosphate 
concentrations were highest near the mouth of the Alafia River (Flannery, 
this report). The historically low dissolved oxygen concentrations found 
in deeper waters were attributed to high benthic oxygen demands of muddy 
high organic sediments. The FWPCA (1969) recommended selective dredging 
of the extensive high organic deposits to improve Hillsborough Bay water 
quality. The recommended dredging has not been performed to this date. 

Taylor and Saloman (1969) collected surface sediments between 1961 
and 1965 from 773 locations in Tampa Bay and the adjacent Gulf of Mexico. 
Samples were analyzed for grain size composition, calcium carbonate 
content, and concentrations of organic carbon and organic nitrogen. 
Although much of Taylor and Saloman’s (1969) data remain uninterpreted, 
Taylor, Hall and Saloman (1970) used the data to relate sediment 
composition to mollusk abundance and diversity at 45 locations in 
Hillsborough Bay. Most deep stations had silty sediments and lacked 
mollusks. Areas lacking mollusks, which included several shallow sandy 
stations, were classified as unhealthy. Unhealthy areas were located 
along the eastern and western shores of the bay and near the mid-bay 
shipping channel. Healthy areas were found at the mouth of Hillsborough 
Bay and in McKay Bay. Unhealthy areas comprised 42% of the bay bottom and 
only 22% of the bottom was considered healthy. 

Doyle, Van Vleet, Sackett, Blake and Brooks (1985) analyzed 
sediment grain size composition and hydrocarbon concentration and 
distribution in Tampa Bay surface sediments during 1984 and 1985. Their 


130 


conclusions concerning sediment distribution and composition were similar 
to those of Goodell and Gorsline (1961). Doyle et al. (1985) suggested 
that fine grained material dominating Hillsborough Bay surface sediments 
is derived from rivers and urban runoff. In situ generation of fine, high 
organic material produced by the flora and fauna within Hillsborough Bay 
was not discussed. Potential areas of widespread hydrocarbon 
contamination were found in upper Hillsborough Bay and the lower portion 
of the Hillsborough River. The rest of Tampa Bay appears relatively 
uncontaminated. 

During the summer of 1986, the Florida Department of Environmental 
Regulation (in cooperation with Science Applications International Corp.) 
photographed the surface sediments in Hillsborough Bay from May 28 to 
June 2, 1986 (SAIC 1987). A vessel-deployed sediment profile camera was 
used at 200 locations with water depths greater than 2m. Results from the 
report were based solely on computer image analysis of the profile 
photographs, referred to as REMOTS technology. No traditional sampling 
methods were utilized. A series of quantitative and qualitative sediment 
characteristics and processes, including the distribution of successional 
stages of benthic macro-invertebrates were mapped from the photographs. 
The report stated that several kinetic regimes influence the sediment 
pattern in Hillsborough Bay. The shallow areas which are subject to 
scouring have well-sorted sandy sediments, while low kinetic deep areas 
in the central axis of the bay have mostly silt-clay size sediments. The 
REMOTS study also documented apparent high sediment oxygen demand (SOD) 
areas where seasonal hypoxia could be expected during the warm months. 
SAIC (1987) recommended long-term monitoring of potentially anoxic areas 
to determine impacts from anthropogenic pollution and overall "health" of 
the bay ecosystem. Several areas were identified along the margin of the 
2m depth contour of Hillsborough Bay which may be degraded by inputs of 
pollutants, mainly stormwater run-off and sewage discharges, including a 
large region south of the Hillsborough River, most of the eastern margin 
of the bay, and two local areas off the Interbay Peninsula. 

SAIC (1987) concluded that all hypoxic areas in Hillsborough Bay 
are located relatively close to shore near point and non-point sources, 
and that the deeper areas generally lack organic loading and hypoxia. The 
study suggested that intrusion of cool oxygenated bottom water from lower 
Tampa Bay may keep the deeper parts of Hillsborough Bay aerobic. SAIC 
(1987) also postulated that bioturbation from the high-order successional 
stage benthic invertebrates living in the deep areas stimulate microbial 
activity, which in turn, prevent the build-up of labile organic matter. 
The last macro-benthic study in Hillsborough Bay was conducted from 1975 
to 1978 (see Santos and Simon 1980). A comprehensive study is presently 
needed to establish the current macro-benthic environment and to evaluate 
SAIC’s (1987) findings. 


131 



CITY OF TAMPA INVESTIGATIONS OF HILLSBOROUGH BAY SEDIMENTS 


FDER Wasteload Allocation 


In 1981, the Florida Legislature repealed a statue requiring 
advanced wastewater treatment (AWT) for domestic wastewater treatment 
facilities constructed after 1972. The statue was replaced by a mandate 
requiring the Florida Department of Environmental Regulations (FDER) to 
specify wasteload allocations on a case-by-case basis for domestic point 
sources. The FDER began a "wasteload allocation" study to evaluate the 
dissolved oxygen and nutrient impacts of Tampa Bay (including 
Hillsborough Bay) surface water dischargers for long-term wastewater 
planning and permitting. A "wasteload allocation" draft report 
(McClelland 1984) was released by FDER in 1984 for review by interested 
parties. Several criticisms of that draft report were communicated to 
FDER by individuals of the local scientific community and the Tampa Bay 
Management Study Commission (Tampa Bay Management Study Commission 1985). 
One major criticism was that the contribution of sediment pollution 
sources was based on insufficient data. 

The City of Tampa (COT) operates an advanced wastewater treatment 
plant with a permitted discharge into Hillsborough Bay of 60 mgd. It was 
in the interest of the COT to cooperate with FDER in obtaining the most 
accurate data for their wasteload allocation study. The Bay Study Group 
(BSG) of the COT Sanitary Sewer Department, in agreement with the FDER, 
launched a two phased sediment project in Hillsborough Bay to, (1), map 
the surface sediment composition, and (2), quantify dissolved nutrient 
fluxes between the water column and sediments through i_n situ 
measurements of sediment oxygen demand (SOD) rates and nutrient exchange 
rates (NERs). Detailed results of the BSG sediment project have been 
submitted to the FDER in two reports (COT 1986a, 1986b). 

Distribution and Description of Hillsborough Bay Surface Sediments 

Phase 1 of the BSG’s sediment project produced a map of 
Hillsborough Bay identifying areas of "sandy" and "muddy" sediments, and 
estimated the areal coverage of those sediment types. Continuous depth 
recording soundings (200KHz transducer) along 29 transects were used in 
conjunction with sediment grain size analyses from 19 stations to produce 
a sediment map. "Mud" was assumed to occur at locations where 50% or 
more (by weight) of sediment particles passed through a 63um mesh sieve. 
"Sand" occurred where less than 50% of sediment particles (by weight) 
passed through a 63um mesh sieve. Grain size analyses revealed that 
sediment compositions, depending on location, ranged from 95.3% "sand" to 
98.9% "mud." 

"Mud" sections along the 29 transects were interconnected based on 
bottom topography and dredging information, thereby producing the map 
shown in Figure 1. The largest expanse of "mud" covered the deeper zones 
of west-central Hillsborough Bay. The BSG concluded the areal coverage of 
"mud" constituted approximately 24% of the bottom of Hillsborough Bay. 


132 







Figure 1. Estimated areal coverage of "mud" in the surface sediments of 
Hillsborough Bay (modified from COT 1986a). 


133 














Thirty years ago, according to grain size contour maps created by 
Goodell and Gorsline (1961), roughly 32% of Hillsborough Bay surface 
sediments were fine grained sediments (mean phi >4). Because they did 
not intend to map fine grained sediments specifically, the areal coverage 
of these sediments was not as well defined as the "mud" areas delineated 
by the BSG (COT 1986a). The disparity of mapping techniques used by 
Goodell and Gorsline (1961) and the BSG prevent any conclusions as to the 
increase or decrease of fine sediments in Hillsborough Bay during the 
past 30 years. However, it is apparent that relatively large areas of 
fine grained surface sediments also existed 30 years ago. 

A representative cross section of Hillsborough Bay sediment types 
was provided by combining subtidal sediment data from the BSG sediment 
mapping effort with intertidal sediment data from another BSG project 
(COT 1988). For descriptive purposes, sediment types were partitioned 
into four groups based on percent sand composition. The sediment groups 
listed in Table 1 are shallow sand, deep sand, intermediate and soft. 

Table 1. Results of grain size and carbon analyses of major sediment 
types in Hillsborough Bay. 



Shallow 

Sand 

Deep 

Sand 

Intermed. 

Soft 

% Sand 

98-100 

82-91 

34-64 

1-16 

% Silt 

0-2 

3-7 

11-35 

24-39 

% Clay 

0-1 

6-11 

21-34 

51-75 

Mean phi 

2.4-3.0 

2.9-3.5 

4.5-5.9 

6.8-7.9 

SD Mean phi 
% Total 

0.4-0.8 

1.8-2.0 

2.2-2.6 

1.2-2.4 

Carbon 

1-7 

5-9 

18-37 

35-56 

% Organic 
Carbon 

0-3 

1-3 

6-10 

15-17 


Shallow sand samples were composed almost entirely of well sorted 
fine quartz sand with a mean grain size of 2.62 phi. Shallow sands occur 
on intertidal and shallow subtidal flats usually at depths less than six 
feet and encompass about 20% of the total bay bottom area. Important 
depositional forces include tides and waves generated by wind and ship 
traffic. Although most areas lack vegetation, some have macroalgae or 
sparse seagrass coverage. Microscopically examined, these sediments 
appear as light colored sand grains intermixed with dark brown 
invertebrate fecal pellets. 

Deep sand samples contained between 83 and 91% of well sorted very 
fine sands with a mean grain size of 3.16 phi. These sediments occur in 
subtidal zones at estimated depths of six to ten feet and cover roughly 


134 




40 to 45% of the bay bottom. Tidal currents and waves are the major 
depositional forces. These sediments often contain benthic assemblages of 
tunicates and tube dwelling amphipods and polychaetes. 

Intermediate sediment samples contained between 34 and 64% of fine 
sands plus a relatively large fraction of clay and silt. They had a mean 
grain size of 5.17 phi, may occur at depths ranging from 8 to 12 feet, 
and cover 15 to 25% of the bay bottom. These sediments contain faunal 
assemblages similar to those found in deep sand sediments. 

Soft sediment samples contained primarily clay and silt (92%), 
with a mean grain size of 7.20 phi. Soft sediments generally occur at 
depths greater than 12 feet and occupy an estimated 15 to 20% of the bay 
bottom. Tidal currents and waves exert relatively weak forces at depths 
greater than 12 ft and so, allows considerable deposition of clay and 
silt-sized material. Dense mats of amphipod feeding tubes are commonly 
observed in some areas. These dense mats can inhibit sediment 
resuspension and may increase the settling rate of suspended particles by 
acting as baffles (Rhoads and Germano 1986). In other areas lacking 
macro-benthic organisms, soft sediments coated with a thin light colored 
sediment layer have been observed (SAIC 1987). The layer contains high 
concentrations of invertebrate fecal pellets and viable phytoplankton 
cells. This surface sediment layer can easily be resuspended and 
represents a highly nutritive energy source for benthic organisms 
including bacteria. 

The organic carbon fraction of total carbon was relatively 
constant, comprising from one-fourth to one-third of the total carbon 
measured in each sediment type. The percents of total and organic carbon 
increased proportionally with increasing percents of mud (% silt + % 
clay) in Hillsborough Bay sediment samples (Table 1). Shallow sand 
sediments were low in both total and organic carbon. Invertebrate fecal 
pellets may be the principal organic carbon source in shallow sands. In 
contrast, soft sediments were high in total and organic carbon. 

Surface Sediment and Water Column Interactions 


Phase II of the BSG’s sediment project involved the quantification 
of the oxygen demand and nutrient contributions that Hillsborough Bay 
sediments have on the overlying water column. Nixon (1981) has shown that 
a large fraction of the organic matter consumed by the benthos is 
associated with a significant flux of inorganic nutrients into the water 
column. 


The BSG made in situ measurements of SODs and NERs in Hillsborough 
Bay during 1986. The SOD chambers and the field procedures employed were 
the same as described by Murphy and Hicks (1985)Nutrients were 


1 Nutrients were analyzed by the Hillsborough County Environmental 
Protection Commission. 


135 





analyzed by the Environmental Protection Commission of Hillsborough 
County. Experiments in "sandy" and "muddy" sediments were performed 
during a winter and a summer month. "Mud" and "sand" locations, as 
previously defined in phase I, contained 85% "mud" (mean phi 6.9) and 88 % 
"sand" (mean phi 3.1), respectively. The SOD and NER results in Table 2 
may be the best available for Hillsborough Bay, but due to the paucity of 
measurements, these results should be considered as initial estimates 
with room for refinement. The highest SOD rate occurred during the summer 
at the "muddy" high organic sediment location and that value was roughly 
twice the rates of all other season-sediment combinations. These 

preliminary results also indicate that sediment releases of inorganic 
phosphate and ammonia were greatest during the summer, and therefore may 
be a function of temperature. Nixon, Oviatt and Hale (1976) related 

benthic ammonia fluxes to bottom water temperatures between 0 and 25°C by 
the equation: 

(1) dc/dt (NH 4 ) = e o-16T+1.90 
where T = temperature in degrees Celcius. 

We calculated flux rates (uM m"^h“^) using this equation with Table 2 
data. The predicted (119) and measured (116) flux rates for winter data 
at 18°C were in close agreement. However, the average measured summer 

flux rate (485) was only half the predicted rate (880) at 30.5°C 

indicating that Nixon et al.’s (1976) function may not apply at 

temperatures above 25°C. 

Table 2. Sediment oxygen demand (SOD, mmoles O 2 m _ 2 h _1 ) and nutrient 

exchange rate (NER, umoles nT^h"*) estimates in Hillsborough 
Bay during 1986. The negative value indicates a decrease in 
water column concentration with time, consequently, a 

meaningful N:P ratio for mud during the winter could not be 

calculated. 


Parameter 

Sand 

WINTER 

Mud 

Sand 

SUMMER 

Mud 

SOD 

8.8 

5.6 

8.1 

14 

NER (PO 4 -P) 

10 

-23 

137 

104 

NER (NH 3 -N) 

111 

121 

396 

573 

N:P ratio 

11 

-- 

2.9 

5.5 


The relatively low N:P ratios of inorganic nutrient fluxes from 
the sediments (Table 2), particularly during the summer, may reflect the 
importance of bacterial dentrification in the sediments. Assuming that 
deposited organic material is mostly derived from phytoplankton, then the 
Redfield N:P ratio of 16:1 might be expected in the regenerated nutrient 
supply. Low N:P ratios measured in benthic nutrient fluxes to the water 


136 








column in several shallow marine environments have been attributed to a 
loss of nitrogen as N 2 from the system by bacterial denitrification 
(Nixon 1981). Natural assemblages of Hillsborough Bay phytoplankton grown 
in chemostat cultures were often found to be nitrogen limited (COT 1983). 
Consequently, the rate of denitrification could influence the supply of 
nitrogen available to support primary productivity. 

The rate of organic matter consumption by Hillsborough Bay 
sediments, in terms of SOD rates, are within the range of rates measured 
in other Tampa Bay embayments as well as other U.S. east coast estuaries 
(Table 3). Annual benthic ammonia flux from Hillsborough Bay sediments 
into the water column were slightly higher relative to other U.S. east 
coast estuarine sediment releases (Table 4). As a growing number of in 
situ benthic flux measurements are generated, there appears to be a 
relationship between the amount of organic matter consumed and inorganic 
matter released by the benthos in terms of ammonia. Nixon (1981) found a 
positive relationship between summer rates of sediment oxygen uptake and 
ammonia release for temperate coastal marine systems with widely ranging 
phytoplankton productivity levels. Rate measurements of those marine 
systems ranged from about 2 to 8 mmoles 02m‘ 2 h" 1 uptake and 25 to 500 
umoles m _2 h _1 ammonia released. Hillsborough Bay falls in the upper 
ranges of those rates (11 0?; 485 ammonia) when the summer data (COT 
1986b) are averaged. The relatively high rates in Hillsborough Bay, a 
subtropical estuary, may simply be due to higher temperature. 


Table 3. In situ sediment oxygen demand (SOD) rate measurements (mmoles 
O 2 m 2 h"f) and water temperatures (°C) during experiments from 
selected U.S. east coast estuaries and Tampa Bay area estuarine 
embayments. 


Water Body 

Patuxent River Estuary 
Patuxent River Estuary 
Narragansett Bay 
Chesapeake Bay 
N. Carolina Estuaries 
Tampa Bay Area: 
Hillsborough Bay 
Hillsborough Bay 
Tampa Bay 
Sarasota Bay 


Temp 

SOD 

24-31 

11.8-19.3 

3-29 

1.3-10.7 

3-21 

0.6-9.4 

Aug-May 

3.9-8.1 

1-22 

0.8-3.2 

17-31 

5.6-14.4 

16-30 

2.1-8.2 

31 

6.9-12.7 

20-30 

4.8-14.2 


Source 


Boynton et al., 1981 
Boynton et al., 1980 
Nixon et al., 1976 
Boynton & Kemp, 1985 
Fisher et al., 1982 

COT, 1986b 

Murphy & Hicks, 1985 
Murphy & Hicks, 1985 
Murphy & Hicks, 1985 


137 








Table 4. Mean annual 

(time weighted) 

flux rates (umoles m' 

V 1 ) of 

ammonia-nitrogen from selected U.S. 
sediments. 

east coast 

estuarine 

Water Bodv 

Temp 

SOD 

Source 


Hillsborough Bay 

111-573 

300 

COT, 1986b 


Patuxent Estuary 

0-1584 

295 

Boynton et al 

., 1980 

Neuse River Estuary 

71-454 

224* 

Fisher et al. 

, 1982 

South River Estuary, NC 

0-267 

113* 

Fisher et al. 

, 1982 

Narragansett Bay 

0-400 

100 

Nixon et al., 

1976 

Buzzards Bay 

2-124 

68 

Rowe et al., 

1975 


*Mean value (not an annual time-weighted average). 


The importance of Hillsborough Bay sediment nutrient fluxes can be 
assessed relative to the nutrient demands of water column primary 
production. Annual Hillsborough Bay phytoplankton production is 620 
gCm"2yr~l based on * 4 C measurements from 1978 to 1983 (Johansson, 
Steidinger and Carpenter 1985). Water column demands were estimated 
assuming that phytoplankton production accounts for nearly all primary 
production and that phytoplankton assimilate N and P in proportion to the 
Redfield C:N:P ratios of 106:16:1. Selected Hillsborough Bay ammonia and 
orthophosphate inputs expressed as a percent of N and P assimilated by 
phytoplankton are shown in Table 5. The sediments can support 34 and 140% 
of the phytoplankton N and P demand, respectively. The Alafia River, a 
major source of dissolved material to the bay, can only supply 0.3 and 
51% of N and P demand, respectively. The COT advanced wastewater 
treatment plant, often cited as a major point source of nutrients, can 
only supply a small fraction of the N demand and 25% of the P demand if 
no other sources were available. 


Table 5. Selected Hillsborough Bay nutrient inputs (NH 3 -N and PO 4 -P) 
expressed as a percent of N and P assimilated annually by 
phytoplankton. N and P assimilation by phytoplankton computed 
using the Redfield C:N:P ratios of 106:16:1. 


NH 3 -N PO 4 -P 



moles m^-yr 

% 

moles m^-yr 

% 

Phytoplankton 

7.8 


0.49 


Sediments 

2.68 

34 

0.67 

140 

Alafia River 

0.024 

0.30 

0.25 

51 

COT AWT Plant 

0.005 

0.06 

0.12 

25 


138 








The supply of phosphate in Tampa Bay, including Hillsborough Bay, 
far exceeds the demand by phytoplankton. According to Fanning and Bell 
(1985) no other estuary they know of has as high a phosphate 
concentration as the Tampa Bay system (average = 14uM). They attribute 
high phosphate concentrations to leaching of Florida’s phosphate beds, 
fertilizer drainage from agricultural lands, and industrial and sewage 
inputs. 


On the other hand, nitrogen supplies are probably the single most 
important limiting nutrient to primary production in Hillsborough Bay. In 
particular, evaluating inputs of ammonia is an important first step in 
assessing the nitrogen budget. Ammonia is the nitrogen form most readily 
assimilated by phytoplankton (Darley 1982, Pennock 1987), and the 
dominant inorganic nitrogen form released from the bottom (Nixon et al. 
1976, COT 1986b). Our measurement showing that sediment recycling 
supports a large fraction of the nitrogen needed for phytoplankton 
production (34%) in Hillsborough Bay are similar to the findings of 
Fisher et al. (1982) for each of ten shallow marine systems (mean = 
35+8.7%). Annually averaged 14 C productivity data for those ten systems 
ranged from 0.15 to 2.0gCm‘ 2 d _1 compared to 1.98gCm" 2 d _1 (Johansson et 
al. 1985) for Hillsborough Bay. Regardless of the system’s level of 
phytoplankton productivity, sediment recycling appears to supply roughly 
one-third of the water column nitrogen demand. Hillsborough Bay’s 
sediment recycling rates lend support to the Fisher, Carlson and Barber 
(1982) observation that system production and benthic nutrient recycling 
are functionally interconnected processes. However, it is important to 
realize that system productivity in estuarine systems, such as 
Hillsborough Bay, may primarily be driven by point and non-point nutrient 
sources, and not by sediment recycling. Increases in point and non-point 
nutrient inputs sustain greater levels of primary production and 
eventually create additional sediments of high organic content. The 
nutrients contained within these sediments are recycled and, in turn, 
further enhance the inorganic nutrient pool available to primary 
producers. 

As part of the FDER wasteload allocation study, McClelland (1984) 
produced a nutrient box model for Tampa Bay. He calculated that all 
non-point and point sources, including storm water runoff, only amounted 
to one-third of the nitrogen released from the sediments. Adding these 
inputs to the benthic fluxes still only account for about 50% of the 
nitrogen needed to support the observed primary production. Other sources 
of nitrogen are supplied by in situ water column regeneration and 
possibly sediment resuspension. Also, some nitrogen could be lost from 
the system by bacterial denitification. These are among several processes 
that have not been addressed in Hillsborough Bay or the Tampa Bay system 
in general. 


139 



CONCLUSION 


The soft, muddy, high organic sediments and their associated fauna 
found in Hillsborough Bay are important for nutrient regeneration and 
oxygen demand. These processes appear to be related to the water quality 
and "health" of the bay ecosystem. The location and areal coverage of the 
soft sediments is relatively well known (see above). Sub-bottom profiling 
by the BSG in 1986 revealed that the soft sediment deposits in central 
Hillsborough Bay may be thicker than 3m in some places. However, the 
recent history and accumulation rate of these sediments is largely 
unknown. 

Doyle et al. (1985) carbon dated the bottom of sediment cores at 
five locations in Tampa Bay including one taken in Hillsborough Bay. We 
used this information and calculated an average sedimentation rate over 
the length of the cores of only 6.0 cm/100 yr. However, this rate may not 
represent sedimentation occurring in the soft areas of central 
Hillsborough Bay, since all cores, except one anomalous core from middle 
Tampa Bay, were taken in sandy sediments. We know that fine sediments 
accumulate rapidly in recently dredged areas with limited circulation. 
For example, rates of 10 cm/yr or more have occurred in Bayboro Harbor 
(Young 1984), a small mid-Tampa Bay embayment, and The Kitchen, located 
in southeastern Hillsborough Bay. 

A detailed study to determine geologically recent sedimentation 
patterns of soft sediments in Hillsborough Bay is presently being planned 
between the BSG and the University of South Florida Marine Science 
Department. The study will attempt to identify controls and processes 
governing recent sedimentation in Hillsborough Bay, including 
anthropogenic impacts by analyzing core samples. A similar study of 
contaminated soft sediments found in the lower Hillsborough River has 
been initiated by the COT Stormwater Division in cooperation with the 
Florida Institute of Technology. 

Information on surface sediments and their relationship to the 
nutrient budget and water quality conditions of Hillsborough Bay is 
critical to realize possible management options for this stressed marine 
ecosystem. Recent improvements in Hillsborough Bay water quality (HCEPC 
1987 and COT 1988) appear related to recent reductions in nutrient 
loadings from sewage (Garrity, McCann and Murdoch 1985) and fertilizer 
industry effluents (Estevez and Upchurch 1985). To effectively alleviate 
eutrophic conditions of an estuary, efforts should be aimed at decreasing 
point and non-point nutrient inputs. Point and non-point nutrient inputs 
may ultimately be the cause of high organic sediments deposits. The 
removal of high organic containing sediment would only result in a short 
term reduction of sediment nutrient inputs. Other nutrient inputs, left 
unchecked, would recreate the high organic sediment deposits previously 
removed. Consequently, costly management undertakings, such as selective 
dredging of these deposits (see FWPCA 1969), may never be needed and must 
be avoided until potential impacts from these sediments on the Tampa Bay 
ecosystem are better understood. 


140 



LITERATURE CITED 


Boynton, W.R. and W.M. Kemp. 1985. Nutrient regeneration and oxygen 
consumption by sediments along an estuarine salinity gradient. Mar. 
Ecol. Prog. Ser. 23:45-55. 

Boynton, W.R., W.M. Kemp and C.G. Osborne. 1980. Nutrient fluxes across 
the sediment-water interface in the turbid zone of a coastal plain 
estuary, pp. 93-109, In: V.S. Kennedy (ed), Estuarine Perspectives. 
Academic Press, New York. 

Boynton, W.R., W.M. Kemp, C.G. Osborne, K.R. Kaumeyer and M.C. 

Jenkins. 1981. Influence of water circulation rate on in situ 
measurements of benthic community respiration. Mar. Biology 65:185-190. 

City of Tampa. 1983. Results of phytoplankton bioassay experiments. 
Report to Florida Dept, of Environmental Regulations. Submitted by City 
of Tampa, Dept, of Sanitary Sewers, Bay Study Group. 40 pp. 

City of Tampa. 1986a. Surface sediment composition and distribution in 
Hillsborough Bay, Florida. Report to Florida Dept, of Environmental 
Regulations. Submitted by City of Tampa, Dept, of Sanitary Sewers, Bay 
Study Group. 16 pp. 

City of Tampa. 1986b. Winter and summer sediment nutrient exchange 
rates in Hillsborough Bay, Florida. Final report to Florida Dept, of 
Environmental Regulation. Submitted by City of Tampa, Dept, of Sanitary 
Sewers, Bay Study Group. 16 pp. 

City of Tampa. 1988. An ongoing survey of Halodule wrightii . Ruppia 
maritima and the alga, Caulerpa pro!ifera , in Hillsborough Bay, Florida. 
Initial assessment and design. City of Tampa, Dept, of Sanitary Sewers, 
Bay Study Group. 24 pp. 

Darley, W.M. 1982. Phytoplankton: environmental factors affecting 
growth. pp. 21-52, In: W.M. Darley, Algal Biology: a physiological 

approach. Blackwell Scientific Publications, London. 

Doyle, L.J., E.S. Van Vleet, W.M. Sackett, N.J. Blake and G.R. 

Brooks. 1985. Hydrocarbons of Tampa Bay: Final report to Florida Dept, 
of Natural Resources. Submitted by University of South Florida, Dept, of 
Marine Science, St. Petersburg, Florida. 193 pp. 

Estevez, E.D. and S.B. Upchurch. 1985. Impact of the phosphate 
industry on Tampa Bay, Florida. Abstract, p. 594, In: S.F. Treat, J.L. 
Simon, R.R. Lewis, III, and R.L. Whitman, Jr. (eds), Proceedings Tampa 

Bay Area Scientific Information Symposium. Bellwether Press. 

Fanning, K.A. and L.M. Bell. 1985. Nutrients in Tampa Bay. pp. 

109-129, In: S.F. Treat, J.L. Simon, R.R. Lewis III, and R.L. Whitman, 


141 









Jr. (eds), Proceedings Tampa Bay Area Scientific Information Symposium. 
Bellwether Press. 

Fisher, T.R., P.C. Carlson and R.T. Barber. 1982. Sediment nutrient 
regeneration in three North Carolina estuaries. Estuarine Coastal Shelf 
Sci. 14:101-116. 

FWPCA. 1969. Problems and management of water quality in Hillsborough 
Bay, Florida. Hillsborough Bay Technical Assistance Project, Technical 
Programs, Southeast Region, FWPCA, Tampa. 88 pp. 

Garrity, R.O., N. McCann and J.D. Murdoch. 1985. A review of 
environmental impacts on municipal services in Tampa, Florida, pp. 
526-550, In: S.F. Treat, J.L. Simon, R.R. Lewis III, and R.L. Whitman, 
Jr. (eds), Proceedings Tampa Bay Area Scientific Information Symposium. 
Bellwether Press. 

Goodell, H.G. and D.S. Gorsline. 1961. A sedimentologic study of Tampa 
Bay, Florida. 21st Internat’l. Geol. Cong., 1960, pt. 23, pp. 75-88. 

HCEPC. 1987. Water Quality 1984-1985 Hillsborough County Florida. R. 
Boler (ed), Hillsborough County Environmental Protection Commission, 
Tampa, Florida. 205 pp. 

Johansson, J.O.R., K.A. Steidinger and D.C. Carpenter. 1985. Primary 
production in Tampa Bay, Florida: A review, pp. 279-298, In: S.F. Treat, 
J.L. Simon, R.R. Lewis III, and R.L. Whitman, Jr. (eds), Proceedings 
Tampa Bay Area Scientific Information Symposium. Bellwether Press. 

McClelland, S. 1984. Draft Tampa Bay 205 (j) water quality impact 
study. Bureau of Water Analysis, Fla. Dept, of Environmental Regulation, 
Tallahassee. 

Murphy, P.J. and D.B. Hicks. 1985. Sediment oxygen demand: processes, 
modeling, and measurement. K.L. Hatcher (ed), Published by Institute of 
Natural Resources, Univ. of Georgia, Athens, Georgia. 

Nixon, S.W. 1981. Remineralization and nutrient cycling in coastal 
marine ecosystems, pp. 111-138, In: B.J. Neilson and L.E. Cronin (eds), 
Estuaries and Nutrients. Humana Press, Clifton, NJ. 

Nixon, S.W., C.A. Oviatt and S.S. Hale. 1976. Nitrogen regeneration and 
the metabolism of coastal marine bottom communities, pp. 269-283, In: 
J.M. Anderson and A. Macfayden (eds), The role of terrestrial and aquatic 
organisms in decomposition processes. Blackwell Science Publ., Oxford, 
England. 

Pennock, J.R. 1987. Temporal and spatial variability in phytoplankton 
ammonium and nitrate uptake in the Delaware estuary. Estuarine Coastal 
Shelf Sci. 24:841-857. 


142 


Rhoads, D.C. and J.D. Germano. 1986. Interpreting long-term changes in 
benthic community structure: a new protocol. Hydrobiologia 142:291-308. 

Rowe, G.T., C.H. Clifford and K.L. Smith Jr. 1975. Benthic nutrient 
regeneration and its coupling to primary productivity in coastal waters. 
Nature 255:215-217. 

SAIC. 1987. A REMOTE sediment profile study of Hillsborough Bay, 
Florida. Report to Florida Dept, of Environmental Regulation. Submitted 
by Science Applications International Corporation, Newport, Rhode Island. 
75 pp. 

Santos, S.L. and J.L. Simon. 1980. Response of soft-bottom benthos to 
annual catastrophic disturbance in a south Florida estuary. Marine 
Ecology Progress Ser. 3:347-355. 

Tampa Bay Management Study Commission. 1985. The future of Tampa Bay. 
Report to the Florida Legislature and the Tampa Bay Regional Planning 
Council. Submitted by the Tampa Bay Management Study Commission, a 
commission of the Tampa Bay Regional Planning Council, St. Petersburg, 
Florida. 195 pp. 

Taylor, J.L., J.R. Hall and C.H. Soloman. 1970. Mollusks and benthic 
environments in Hillsborough Bay, Florida. Fishery Bulletin 68:191-202. 

Taylor, J.L. and C.H. Soloman. 1969. Sediments, oceanographic 
observations, and floristic data from Tampa Bay, Florida and adjacent 
waters 1961-1965. U.S. Fish and Wildlife Service, Data Report 34. 562 

pp. 

Young, R.W. 1984. A geochemical investigation of dredging in Bayboro 
Harbor and the Port of St. Petersburg. Masters Thesis, University of 
South Florida, Dept, of Marine Science. 152 pp. 


143 


STORMWATER INPUTS TO TAMPA AND SARASOTA BAYS 


Ronald F. Giovannelli 
Florida Land Design & Engineering, Inc. 
Tampa, Florida 


INTRODUCTION 


This paper presents information regarding stormwater inputs to 
Tampa and Sarasota Bays. Discussions will center primarily on the urban 
rather than agricultural aspects of stormwater. Information will 
supplement previous data on overall watershed characteristics and stream 
or river flows to Tampa and Sarasota Bays. Unique rainfall 
characteristics for the Tampa Bay area as they relate to runoff quantity 
and quality will be discussed, as well as urbanization patterns and 
changes in land use which cause natural stream flow to be characterized 
as urban runoff. Runoff volumes are compared for the Tampa and Sarasota 
Bay systems to other Gulf coast areas. In addition, loadings for 
selected constituents are presented for various land use and treatment 
scenarios. 


PHYSICAL SETTING 


The watersheds tributary to Tampa and Sarasota Bays are shown in 
Figures 1 and 2, respectively. For the Tampa Bay system the surface 
water area of Tampa Bay is approximately 400 square miles, while the area 
of tributary watershed is approximately 1800 square miles, a ratio of 4.5 
to 1, watershed to bay surface area (Treat, 1982). In the Sarasota Bay 
system the water surface area is approximately 40 square miles and the 
tributary area is approximately 30 square miles excluding the Phillippi 
Creek watershed, which is approximately 50 square miles, a ratio of 0.75 
(or 2 to 1, depending upon whether Phillippi Creek is included). 


PREVIOUS RESEARCH 


A significant amount of data has been collected on urban runoff in 
selected tributaries to Tampa Bay. Prior to 1975, information was 
primarily quantity-based and resulted from studies on flooding. From 
1975 to 1983, however, two major projects were conducted which resulted 
in significant research on rainfall, runoff quantity, and runoff quality. 
The first of these two studies was a cooperative program instituted by 
the U.S. Geological Survey (USGS) and five local governments between 1975 
and 1979. In this study, nine urban gauging stations were installed in 
mixed land use basins ranging from approximately 0.3 to 3.0 square miles. 
Both runoff quantity and quality were collected through the duration of 
the study and published in two separate USGS reports, one quantity based 
(Lopez, 1983) and one quality based (Lopez, 1984). 


144 






145 













146 































In 1980 the city of Tampa was selected by the U.S. Environmental 
Protection Agency (EPA) as one of 28 locations for the Nationwide Urban 
Runoff Program (NURP). This was a three-year study during which four 
homogeneous land use gauging stations were implemented: low and high 
density residential, commercial, and highway watersheds which were less 
than one square mile. Rainfall quantity and quality, and runoff quantity 
and quality were collected at the sites. By selecting homogeneous land 
uses this study contrasted the previous USGS study. 

The location and source of the previously described urban runoff 
stations are shown graphically in Figure 3. Information is available 
from 13 stations surrounding Tampa Bay. However, little or no data is 
available on watersheds tributary to Sarasota Bay, which appears to be 
an area where data collection is needed in order to more fully 
characterize urban non-point source pollutant loadings. 

As a result of the USGS and NURP data, regression equations were 
developed for selected constituents which allow the estimation of non¬ 
point source pollutants to Tampa Bay. This information may be 
transferrable to the tributaries of Sarasota Bay; however, it would be 
advantageous to have data with which to verify the validity of equations 
and develop site specific information on the Sarasota Bay area. These 
regression equations and estimates of non-point source loadings were used 
in Waste Load Allocations (WLA) studies for both Tampa and Sarasota Bays. 
Major reports which have been produced in the Tampa Bay area containing 
urban runoff data or information have been utilized in preparation of 
this paper. These reports are listed in the Literature Cited. 


RAINFALL 


The Tampa Bay area experiences a sub-tropical pattern of rainfall 
which produces unique seasonal characteristics which affect the quantity 
and quality of urban runoff. It is important to describe the rainfall 
characteristics of the Tampa Bay area in order to have an appreciation of 
this seasonality and variability in rainfall. Data which are presented 
within this section were developed as part of the NURP studies by Metcalf 
& Eddy, 1983, utilizing hourly rainfall data from Tampa International 
Airport from 1948 through 1979. During that period the variation in 
total annual rainfall was approximately 29 to 74 inches. This is a 
variation from the most dry to most wet year of approximately 45 inches. 
Variations of mean monthly rainfall ranged from approximately 1.4 inches 
in May to 8.5 inches in July, with approximately 60% of the total annual 
rainfall occurring from June through September. This summer rainy season 
produces the most significant portion of the runoff volume to the bay 
systems. The rainfall data reveal that approximately 90% of all storms 
which occur in the Tampa Bay area have 1.0 inch or less volume. 


147 




148 













A great deal of variability in rainfall occurs between summer 
thundershowers and winter frontal storms. During the summer months this 
area experiences short duration thunderstorms which produce most of the 
rainfall. Approximately 60% of all storm events which occur in the Tampa 
Bay area have a duration of four hours or less (Figure 4). Summer 
thundershowers also exhibit higher intensities than the longer, less 
intense winter frontal storms. Another important characteristic of 
rainfall in this area is the time between storms which relates directly 
to pollutant build up and to the concentration of storms washed off 
developed areas. Thirty percent of all storms occurred with a separation 
of 24 hours or less, 40% had a separation of 48 hours or less and 50% of 
all the storms occurred within 72 hours of each other. 

When compared to runoff quantity and quality data, these weather 
data reveal that during the summer months (June - September) storms of 
short duration, high intensity, and short periods of antecedent dry 
conditions produce high volumes of runoff with generally lower 
constituent concentrations due to very little opportunity for build up of 
particulate matter. On the other hand, winter frontal storms are of 
longer duration, with less intensity and have much longer periods of time 
between storm events. This allows particulate matter to build up with 
concentrations generally higher for winter runoff events. These factors 
are important to the ecology of the bay with regard to mass loadings for 
certain parameters and the event specific toxicity of others. 


LAND USE AND URBANIZATION 


Urbanization in the Tampa and Sarasota Bay areas has resulted in 
the modification of natural watersheds to residential neighborhoods, 
apartment complexes, industrial, commercial, and agricultural land uses. 
As a result of this urbanization, the water quality and quantity entering 
Tampa and Sarasota Bays has been modified. Urbanization began in the St. 
Petersburg, Tampa, and Bradenton/Sarasota areas and spread out from those 
urban cores. Urbanization within Pinellas County has been most rapid, 
encompassing nearly the entire County. Urbanization in Hillsborough 
County has spread out radially to the northwest and east from the City of 
Tampa. Development around Bradenton/Sarasota has been primarily close to 
the coast between the two cities. Current land use distributions within 
the areas tributary to Tampa Bay are shown in Table 1. Only 16.6% of the 
total area of the watershed is forest or natural. Approximately 60% has 
been developed as pasture and crop land, and approximately 25% of the 
entire 1,800 square mile watershed is urbanized. 


149 




150 













































Table 1. Land use distribution within Tampa Bay tributary watershed 
(1983). (From Hartigan 1984) 

Land Use % Total Area Subtotal 


Forest 

16.6 

16.6 

Cropland/other rural 

21.3 


Pasture 

38.9 

60.2 

Urban residential/other 

16.2 


Urban commercial/industrial 

7.0 

23.2 


100.0 

100.0 


Such land use distribution can be translated into geographically 
specific areas that produce modifications to the quantity and quality of 
runoff (Figure 5). Areas of generally high, medium and low concentration 
of urbanization directly relate to areas which produce high, medium, and 
low volumes of runoff and poor, moderate and good (relatively) water 
quality from runoff. 


URBAN STORMWATER CHARACTERISTICS 


It is important to describe the characteristics of the stormwater 
collection systems in the Tampa and Sarasota Bay areas in order to fully 
understand the quantity and quality of resulting runoff. The Tampa and 
Sarasota Bay areas are fully served by separate storm and sanitary sewer 
systems. Unlike many areas in the northeast and other parts of the 
country which have combined systems, this area is fortunate in that most 
if not all sanitary sewage is collected, treated, and then discharged in 
dedicated systems on a continuous basis, whereas stormwater is collected 
in separate systems and may or may not be treated. The most heavily 
urbanized areas shown in Figure 5 are serviced by closed storm sewer 
systems which consist of inlets, pipes, collector systems and major 
outfalls. Some major ditches and outfall canals exist in the heavily 
Urbanized areas. In the light urbanized areas or areas of moderate 
urbanization, stormwater collection is accomplished more through 
neighborhood ditches, rural roadway sections and canals. 

The Tampa Bay area has one of the highest rates of runoff in the 
entire gulf area. The density of development in Pinellas County produces 
runoff intensities comparable only to New Orleans and Houston (Figure 6). 
Combining densely populated, established areas and rapidly urbanizing 
surrounding areas results in the highest runoff volumes of any 
metropolitan area (multiple counties) tributary to the Gulf of Mexico 
(National Ocean Service, 1985). Needless to say, such level of 
urbanization and runoff volume results in local flooding problems. It 
would be a fair assessment to say that the primary focus of local 
attention at the City, County, and State level is on the quantity of 
runoff and flooding, rather than water quality under existing conditions 
with current federal funding and local/state regulatory mandates 
(treatment for new construction only). 


151 










152 












FIGURE 6 STORMWATER RUNOFF 
FROM URBAN AREAS 

Millions of gallons of runoff per square mile per 
year, circa 1980. 

SOURCE: NATIONAL OCEAN SERVICE. 1985 _ 


MANATEE 

CO. 


Nj 20-49 

I I 

D 


POLK CO. 


153 










Storm sewer systems that have been put in place during the last 
century were built without benefit of water quality treatment or best 
management practices. Water quality regulations in the state of Florida 
and specifically in the Tampa and Sarasota Bay areas were being developed 
during the period from approximately 1980 to 1982, were formalized 
between 1982 and 1984 and began rigorous implementation from 1984 to the 
present. Because the vast majority (possibly up to 90% or more) of the 
current urban buildout in areas tributary to Tampa and Sarasota Bay 
occurred prior to 1982, it may be assumed that these areas are 
discharging untreated, non-point source pollution. 

In order to better illustrate the effects of urbanization and non¬ 
point source controls on stormwater loadings, the results from two 
wasteload allocation studies performed either by or at the request of the 
Florida Department of Environmental Regulation (FDER) can be presented. 
Non-point source loading was one of the major pollution inputs to the 
wasteload allocation. Estimates of non-point source loadings in both the 
Tampa and Sarasota Bay studies were calculated using the USGS regression 
equations and/or NURP data. 

The analysis for the Tampa Bay system was performed using three 
land use conditions: 1) the entire tributary watershed as 100% forested 
or natural; 2) current land use distributions; and 3) future land use 
distributions. 


Table 2. Ratios of natural and year 2000 land use loadings to current 
(1983) conditions. (From: McClelland, 1984.) 

Loading Ratio* 


Land Use 

Total N 

Total P 

m 5 

Natural (100% forested) 

0.64 

0.29 

0.38 

Year 2000 with no NPS controls 
Year 2000 with urban and 

1.10 

1.05 

1.13 

agricultural BMP’s 

0.99 

0.85 

0.99 

*Numerical average of values for Old Tampa Bay, 
Main Bay. 

Hillsborough 

Bay and 


Using the existing condition as a base, estimates for the 
contribution of "Natural Conditions" ranged from 29% to 64% of the 
current loading for phosphorus, BOD, and nitrogen. In other words, only 
29% to 64% of the current loading of these constituents reached the Tampa 
Bay system under natural conditions. Between 110% to 113% times the 
loading occurs for future conditions with no controls and from 85% to 99% 
occurs for future conditions with controls. 


154 






The results of the wasteload allocation performed for Sarasota Bay 
indicates that this system is much more sensitive to urban runoff 
loadings. Loading values for the wasteload allocation study in Sarasota 
Bay are shown in Table 3. Non-point sources contribute by far most of 
the total suspended solids and 30 to 50% of the nitrogen and phosphorus 
loadings to the bay, respectively. 


Table 3. Comparison of total loads to Sarasota Bay 1981-1982 (lbs. per 
day). (From Priede/Sedgwick, Inc. 1983.) 



TSS 

IN 

IP 

Point sources (measured) 

166 

1,079 

253 

Non-point sources (estimated) 

3,021 

291 

118 


These data indicate that the levels of non-point source loadings 
to Tampa and Sarasota Bays are significant with existing levels of 
urbanization. Realizing that urbanization will continue as the 
population in Florida continues to increase, non-point source loadings 
will have to be dealt with. New sources as well as existing development 
will have to be examined in order to manage and improve runoff quality. 
The retrofitting process for stormwater quality treatment in existing 
developed areas will be costly, controversial and time consuming. 


155 



LITERATURE CITED 


Hartigan, J.P., S.A. Hanson-Walton. 1984. Tributary streamflows and 
pollutant loadings delivered to Tampa Bay. Fla. Dept. Environ. Reg., 
Tampa, FL. 

Lopez, M.A. and R.F. Giovannelli. 1984. Water quality characteristics 
of urban runoff and estimates of annual loads in the Tampa Bay area, 
Florida, 1975-80. U.S. Geol. Surv. Water Resour. Invest. Rept. 83-4181. 
Tallahassee, FL. 

Lopez, M.A. and W.M. Woodham. 1983. Magnitude and frequency of flooding 
on small urban watersheds in the Tampa Bay area, west-central Florida. 
U.S. Geol. Surv. Water Resour. Invest. 82-42. Tallahassee, FL. 

McClelland, S. 1984. Tampa Bay 205(j) Water Quality Impact Study. 
Water Quality Analysis Section. Bureau of Water Analysis. Fla. Dept. 
Environ. Reg., Vol. 2. 

Metcalf & Eddy, Inc. 1983. Tampa Nationwide Urban Runoff Program 

Phase II, Task II.2. Rainfall Quantity Analysis. 

National Ocean Service. 1985. Gulf of Mexico coastal and ocean zones 
strategies assessment. Data Atlas, Dept, of Commerce, NOAA. 

Priede/Sedgwick, Inc. 1982. Tampa Nationwide Urban Runoff Program 

Phase II, Task II.4. Runoff Characterization Watershed Selection. 

Priede/Sedgwick, Inc. 1983. Final Sarasota Bay water quality study. 
Fla. Dept, of Environ. Reg. 

Treat, S.A.F., J.L. Simon, R.R. Lewis, III, and R.L. Whitman, Jr. 1982. 
Proceedings Tampa BASIS. Tampa Bay Area Scientific Information 
Symposium. Bellwether Press, Tampa, FL. 

U.S. Geological Survey. 1984. Water Resources Data, Florida. Water 
Year 1984. FL-84-3A. 

Wang, J., N. Rooij, J. Ryther, and A. Huggins. 1985. Effects of point 
and non-point sources on Sarasota Bay. Rept. to the City of Sarasota, 
Fla., by ERM, Inc. 


156 



HEAVY INDUSTRY OF TAMPA AND SARASOTA BAYS 


T. Duane Phillips 
Kumar Mahadevan 
Mote Marine Laboratory 
Sarasota, Florida 

Sandra Tippin 
Richard D. Garrity 

Florida Department of Environmental Regulation 
Tampa, Florida 


INTRODUCTION 


Tampa and Sarasota Bays and their tributary rivers and creeks have 
long been used as receiving bodies for man’s domestic and industrial 
wastes. Tampa’s first centralized sewage system was built in the 1890s 
and discharged directly into the Hillsborough River and Hillsborough Bay 
(Garrity, McCann, and Murdoch 1985). As early as 1929, the Alafia River 
was used as a dump for both rock and waste waters by the phosphate 
industry (Lewis and Estevez 1988). Galtsoff (1954) stated more than 30 
years ago that Tampa Bay was "grossly polluted" because of municipal 
sewage discharges and industrial wastes from 6 phosphate mines, several 
citrus canneries and miscellaneous plants. He also noted that most of 
Sarasota Bay was closed to shellfishing because of pollution. A listing 
of waste discharges into the two bay systems in 1968 included 18 
industrial sources in Tampa Bay and 15 industrial sources in Sarasota Bay 
(McNulty, Lindall, and Sykes 1972). Discharges into Sarasota Bay were 
primarily from small laundries with average daily discharges of 0.01 
million gallons/day (mgd). Tampa Bay industrial sources included citrus 
processors, chemical companies, electronics manufacturers, and a variety 
of other industries; the average daily discharge for most of these 
industries was reported as unknown. A review of point source discharges 
in the Tampa Bay area in 1980 listed 59 sources (Moon 1985). This list 
includes both domestic and industrial discharges but did not include 
specific information regarding the types or quantities of materials 
discharged. 

Current records of the Florida Department of Environmental 
Regulation (FDER) show a total of 75 permits for the discharge of 
industrial wastes into the surface waters of Tampa and Sarasota Bays. 
Three power plants located on Tampa Bay which withdraw bay water for 
condenser cooling and discharge thermal effluent into the Bay are not 
included in these FDER permits. Eighteen of the 75 permits are for 
sources considered as major discharges; the remainder are for minor 
discharges. Sewage and sewage treatment plant effluents are not included 
in this total. 


157 



SARASOTA BAY 


The area surrounding Sarasota Bay has never been heavily 
industrialized. Fourteen of the 15 sources of industrial discharges into 
the bay listed by McNulty et al. (1972) were laundries or car washes. 
The remaining source, a manufacturer of television and communication 
equipment, was listed as the largest source of discharge into the bay via 
Phillippi Creek with average daily discharges of 0.02 mgd. None of these 
sources hold a current FDER discharge permit and presumably have either 
been connected to municipal sewage systems or have ceased discharging 
wastes. 


The City of Sarasota reverse osmosis (RO) water treatment plant is 
the only source of industrial discharge into Sarasota Bay currently under 
permit by DER. This source is considered by FDER to be a major 
discharge. Several smaller RO plants discharge wastewaters into coastal 
bays just to the south of Sarasota Bay proper. The effect on the overall 
water quality of Sarasota Bay caused by industrial discharges is probably 
insignificant when compared with the effects of nonpoint source runoff 
(Giovannelli, this report) and sewage plant discharges. 


TAMPA BAY 


Historically the phosphate and related chemical processing 
industries have been the main source of industrial wastewater discharges 
into the Tampa Bay system. Seven of the 18 sources of discharge in the 
late 1960’s were of this type (McNulty et al. 1972). In 1987, of the 18 
active permits issued by the FDER for major sources of industrial 
discharge, nine were for wastes discharged by facilities which 

manufactured sulfuric and phosphoric acids, triple superphosphate and 
other phosphate related compounds. The remaining major sources of 

discharge consisted of two citrus processors, the City of Tampa water 
treatment plant, and 6 power plant discharges. Three of these power 

plants withdraw a combined total of 1942 mgd of bay water for condenser 
cooling. The location of major industrial waste discharges into the 
surface waters of Tampa Bay and its tributaries are shown in Figure 1. 
Discharges from phosphate processors and power plants are important 

because of the number and the quantity of their effluents. Specific 
problems associated with these industries will be discussed in greater 
detail. 


Along with the 18 major discharges, an additional 57 minor sources 
have active FDER discharge permits or are under enforcement for 
unpermitted discharge. These sources represent a diversity of industrial 
activities including several phosphate and fertilizer producing 
facilities, citrus canneries, laundries, and petroleum refining and 
storage operations. Only two minor sources of industrial surface water 
discharge are presently permitted by FDER in Sarasota County. Both 
permit holders are shell pit operations which occasionally discharge 


158 




28*15 


82*45 


82 * 30 ' 


28 * 00 '- 


27*451 


27 * 30 ' 



27 * 45 * 


27 * 30 * 


82 * 45 * 


82 * 30 ' 


82 * 15 * 


Figure 1. Sources of industrial discharge into Tampa Bay. 


159 











water generated from the dewatering or washing of sand and fill mined at 
the sites.In general, the makeup and quantities of many industrial 
discharges into Tampa Bay have not been well documented (Tampa Bay 
Regional Planning Council 1985). 

Most of the industrial development in the Tampa Bay area has 
occurred on the northern and eastern sides of Hillsborough Bay primarily 
due to the presence of phosphate deposits east of the bay and the 
subsequent development of the Port of Tampa (Tiffany, this report). 
Hillsborough Bay has therefore received the greatest quantities of 
industrial wastes through its tributary rivers and creeks. One of the 
most heavily industrialized tributaries is Delaney Creek, a small creek 
which drains approximately 11,069 acres on the northeastern shore of 
Hillsborough Bay (TBRPC 1986b). Delaney Creek has been the receiving 
body for the wastes from a fertilizer manufacturing plant, plants which 
manufacture lead acid batteries, a trucking company, and at least 15 
wastewater treatment plants. Although the creek is designated as Class 
III waters as defined by the Florida Administrative Code, Chapter 17-3 
(recreation and propagation and management of fish and wildlife), it does 
not meet these standards. A recent study of the minor tributaries of 
Tampa Bay has resulted in several recommendations for the restoration and 
management of Delaney Creek (TBRPC 1986b). 

Phosphate Industry 

Phosphate deposits were discovered in the 1880’s in the Bone 
Valley region of Polk County east of Tampa Bay. This discovery not only 
led to direct impacts on the bay’s waters, but also greatly influenced 
the development of the Port of Tampa (Fehring 1985; Tiffany, this 
report). Small scale mining operations began in 1888 when the Arcadia 
Phosphate Company shipped ten carloads of ore mined from the Peace River 
at Arcadia to a fertilizer works in Atlanta (Blakey 1973). The mining 
industry gradually grew during the early part of the 20th Century. 
During this period most of the high grade ore was shipped overseas; the 
lower grade ore was used domestically as fertilizer. Tremendous 
expansion of mining activities occurred following World War II in 
response to the growing worldwide demand for phosphate fertilizers. 
During the late 1940’s and early 1950’s, the industry began to construct 
chemical plants making phosphoric acid, superphosphate, triple 
superphosphate and other concentrated phosphate products for fertilizer. 
The industry continued to expand in the 1960’s with production reaching 
its zenith in 1967. This industry has suffered declines in recent years 
due in part to increased phosphate production worldwide and uncertain 
economic conditions. 

Several activities are associated with the phosphate industry in 
southwest Florida, including mining and beneficiation of the ore, 
transportation of the ore and fertilizer products, and processing the raw 
ore into concentrated compounds for fertilizer. Each of these activities 
has caused environmental problems. Strip mining, for example, causes 
habitat loss and can contaminate both surface and groundwaters. Spillage 
during transport enriches waterways and causes noxious algal blooms. 


160 



Beneficiation is the initial processing and concentration of the 
phosphate ores near the mine site. After the overburden is removed,the 
ore is scooped from the ground and transported as a slurry to a nearby 
processing plant. The ore is crushed, washed, separated from the clay 
and sand, sized through a series of screens, and dried. This process 

creates a slime of water and finely ground clay and sand which has no 

economic use and must be stored and dewatered. Dewatering requires a 
period of several years due to the small size of the clay particles, and 
the slimes are stored in large, diked impoundments. Retaining dikes have 
broken a number of times over the years, releasing large quantities of 
slime into both the Peace and Alafia River. These breaks have resulted 
in vegetation being covered by thick layers of slime for miles downstream 
and have caused massive fish kills. 

Chemical plants which process the raw phosphate ore into enriched 
phosphate compounds used in fertilizer present a different set of 
potential problems. Phosphate rock, as mined, is chemically bound to 

fluoride, which makes it practically insoluble in water. The fluoride 

must be removed before the ore can be processed further. Fluoride 
removal is accomplished by the addition of heat or acid, which releases 
free fluoride. Gaseous fluoride is highly toxic to plants, animals, and 
humans. In the past, fluoride was released to the atmosphere, but 
following a public outcry in the 1950’s after agricultural crops and 
cattle began dying, the industry undertook measures to recover the 
fluorides. Fluoride is produced in almost every stage of chemical 
manufacture (Blakely 1973), and one chemical plant located on Tampa Bay 
near the mouth of the Alafia River discharged fluorides directly into 
Tampa Bay for many years. In seawater, fluoride reacts with calcium 
carbonate to form fluorite. Fluorite forms a hard crust on the bay 
bottom and destroys benthic infauna. These deposits can extend hundreds 
of meters from the discharge. At this plant, areas of continous fluorite 
crust and fluorite chips cover nearly 100 acres of bay bottom. 

Gypsum is another byproduct of the enrichment process. Like the 
slimes generated at the mine site, gypsum must be dewatered and is stored 
at the chemical plants in large impoundments called gypsum stacks. 

Gypsum stack wastewaters are treated by liming and settling before they 
are released into Tampa Bay. Frequent spills have occurred from the 
gypsum stacks at the two chemical plants located on Tampa Bay causing 
adverse environmental effects. 

Many environmental problems associated with the phosphate industry 
have been eliminated by measures to control discharges, but potential 

problems of spills from mine slime ponds and chemical plant gypsum stacks 
remain. The slowdown of the phosphate industry has raised the 

possibility of the closure of mines and chemical plants. Bay management 
plans must include provisions to ensure that, following closure, slime 
ponds and gypsum stacks are sealed and properly maintained to prevent 

future catastrophic spills of toxic substances into the environment. 


161 


Power Plants 


There are currently five steam electric generating plants located 
along Tampa Bay which withdraw bay water for once-through condenser 
cooling (Table 1). Approximately half of the generating units are more 
than 30 years old, and the oldest --Units 1 and 2, Tampa Electric 
Company’s (TECO) Hookers Point Plant-- are approaching 40 years of age. 
Only in the last 20 years with the construction of ever larger generating 
units and their concomitant increases in cooling water withdrawals have 
power plants been recognized as major sources of industrial discharge. 
The 15 units constructed prior to 1965 utilize a combined total of 1,721 
mgd for cooling, whereas the 6 units built since 1965 withdraw a combined 
total of 1,987 mgd, nearly three times the amount per unit. 

The primary environmental impacts caused by plants which use once- 
through cooling are of three types; one concerns the discharge of heated 
effluent, and the other two are associated with the withdrawal of cooling 
water (Figure 2). Thermal discharges can have adverse effects on the 
biota in the vicinity of the power plant. Impingement is the removal and 
death of organisms trapped on plant intake screens. Entrainment causes 
death of planktonic organisms carried through the plant cooling system. 
Additional adverse impacts can be caused by the addition of chlorine at 
plant intakes to reduce in-plant fouling, runoff from coal storage piles, 
and discharges from slag and ash settling ponds. The slag handling 
system at the Big Bend Station, for example, uses an average of 7 mgd in 


conjunction with a settling 
into Tampa Bay (TBRPC 1983). 

pond. 

This water 

is ultimately 

discharged 

Table 1. Five power plants 

located 

in Tampa Bay (from TBRPC, 

1985). 

Hookers 


Big 



Characteristics Point 

Gannon 

Bend 

Higgins 

Bartow 

1) Numbers of units 

5 

6 

4 

3 3 

2) Number of pumps 

3) Start-up dates: 

10 

12 

8 

6 6 

Unit 1 

1948 

1957 

1970 

19511958 

Unit 2 

1948 

1958 

1973 

19531961 

Unit 3 

1950 

1960 

1976 

19561963 

Unit 4 

1953 

1963 

1985 

__ __ 

Unit 5 

1955 

1965 


__ 

Unit 6 

-- 

1967 

-- 

-- -- 

4) Nameplate MW 233 

1,270 

1,823 

138 

494 

5) Total flow (MGD) 

257 

1,267 

1,388 

234 561 


MW = megawatts; MGD = million gallons per day. 


162 





LINS SYSTEM COOLING SYSTEM 



163 























In southern estuaries like Tampa Bay, thermal impacts associated 
with the heated water discharge initially caused the most concern among 
regulatory agencies. Thermal effects are the most visible of power plant 
impacts; steam rises from the water surface on cool days; rafts of foam 
float on the discharge water; and once abundant grassbeds are greatly 
reduced in size or disappear altogether. Several studies have been 
conducted to determine the ultimate impact of thermal discharges at power 
plants on Tampa Bay and in other nearby estuaries. Studies of the 
benthic fauna at TECO’s Big Bend Station on eastern Hillsborough Bay 
(Mahadevan, Culter and Yarbrough 1980) have indeed found that thermal 
effects are severe in the vicinity of the plant discharge. These effects 
are manifested by low overall faunal densities, an abundance of 
opportunistic and pollution indicator species and dissimilarities with 
unaffected open bay stations. These effects, however, were limited to 
the main discharge canal (Figure 3). Mild adverse effects represented by 
a higher incidence and abundance of opportunistic species and lower 
species diversity were limited to a 1 km area outside the plant discharge 
canal. Impacts caused by plant cooling water discharges were difficult 
to discern from the wide seasonal and year-to-year fluctuations in the 
benthic community (Figure 4). Overall, the studies concluded that 
adverse thermal effects were minimal. 

Impingement of fishes and macroinvertebrates on the travelling 
intake screens was also studied at Big Bend (TECO 1980b). These studies 
found that an average of 132 fishes and 125 macroinvertebrates were 
impinged per unit per day. Dominant species trapped on the screens were 
sand seatrout, bay anchovies, horseshoe crabs, and pink shrimp. Based on 
these studies it was concluded that impingement at Big Bend was 
negligible in comparison to the total population and the sport and 
commercial catch. These impingement rates were deemed to be acceptable 
at Big Bend. 

Studies designed to quantify the levels of entrainment of fish 
eggs and larvae through condenser cooling systems have been conducted at 
three of the five power plants on Tampa Bay. These studies found that 
entrainment levels were high at all three plants (Table 2). At Big Bend, 
for example, an estimated 86 billion (8.6 x 10*°) fish eggs and 26 
billion (2.6 x 10*°) fish larvae were entrained per year by the plant 
(Phillips, Lyons, Daily and Sigurdson 1977). The majority of these were 
eggs and larvae of forage species such as bay anchovies, silver perch, 
gobies and blennies. Annual entrainment by all five power plants located 
on Tampa Bay has been estimated to be 2.74 x 10 11 fish eggs and 8.30 x 
10j0 fish larvae which ultimately results in the annual removal of 2.84 x 
10 10 (nearly 3 billion) harvestable adults from the Tampa Bay commercial 
and recreational fishery (TBRPC 1985). Regulatory agencies ruled that 
entrainment levels at Big Bend were unacceptable and that offstream 
cooling or some alternate technology needed to be evaluated. 


164 



165 


Figure 3. Thermal effect zones at the Big Bend Power Plant (from TEOO 1980). 
















































166 







Table 2. Comparison of estimated entrainment from three power plants in 
Tampa Bay. 


PLANT DATA: 

Units 

Hiqqins 1 

3 

Biq Bend 2 

3 

Bartow 3 

3 

Circulating Pumps 

6 

6 

6 

Volume (MGD) 

234 

1,388 

561 

ENTRAINMENT ESTIMATES: 

Total Eggs 5.9 x 10 9 /9 mo 

8.6 x 10 10 /yr 

5.2 x 10 1 °/9 mo 

Total Larvae 3.8 

x 10 9 /9 mo 

2.6 x 10 10 /yr 

5.3 x 10 9 /9 mo 


j-Weiss et al. 1979 

^Phillips et al. 1977 

^Florida Power Corporation 1986. 


Several methods to reduce entrainment were considered (TBRPC 
1986b). One alternative to offstream cooling was to backfit the intakes 
of two units with continuously-washed, fine-mesh screens and an organism 
return system. If successful, this system could be an appealing option. 
At minimal cost, it would reduce the combined entrainment of four units 
to below that of three units fitted with conventional screens. Studies 
to evaluate the feasibility and effectiveness of installing a fine mesh 
screen system were conducted in 1980 on a prototype intake structure 
constructed in the plant intake canal. Survival of fish larvae impinged 
on the prototype fine mesh screen was disappointing, ranging from 0 to 
22% for the most abundant species. On the other hand, approximately 80% 
of bay anchovy eggs and 95% of drum eggs, the two most abundant egg 
types, hatched after the entrainment and wash procedure. Survival of the 
larvae of commercially abundant decapod larvae, pink shrimp (85%) and 
stone crab (92%), was also high. These survival rates were determined to 
be acceptable and fine mesh screen intake structures were subsequently 
built for the two units. Other power plants around the bay have not been 
adapted to reduce entrainment, however. 


167 








SUMMARY 


Industrial development came late to the Tampa Bay area. Phosphate 
mining and processing, once the economic mainstay of many bay area 
communities, began less than 100 years ago. It was not until after World 
War II that explosive population growth and enormous expansion of the 
phosphate industry occurred simultaneously. This combination demanded 
the construction of more and larger power plants to supply electricity to 
light and cool homes and businesses, as well as to meet the needs of the 
increasingly mechanized phosphate industry. The citrus processing 
industry also continued to grow during this period, and its products are 
now marketed worldwide. 

Resources in the early days, including both land and water 
resources, were considered to be limitless. Blakey (1973) in his 
overview of the prevailing mentality stated: 

Men slashed the earth in the pursuit of raw materials, and 
consideration of immediate profit dictated the relationship 
with the land. Capitalism and free enterprise rolled up 
their sleeves in a "lowest cost conspiracy" with the 
consuming public. Industry developed the resources and 
produced the goods at the lowest possible cost, and the 
public joyously bought the goods to enjoy a better life. 

Waste materials were disposed of at the lowest cost wherever it was 
convenient -- a nearby river, or directly into Tampa Bay. 

As the population of the Tampa Bay area continued to grow, the 
need for open spaces, clean water for fishing and swimming, and the 
desire to eliminate noxious odors emanating from the bay became apparent. 
Environmental controls were gradually instituted, and untreated wastes 
could no longer be dumped indiscriminately. 

Environmental impacts resulting from man’s past carelessness 
should serve as a reminder for future generations that vigilance must be 
maintained. Future needs include better maintenance of gypsum stacks at 
chemical processing plants, as evidenced by the spill of nearly 13 
million gallons of acid slime which inundated tidal marshes in March 1987 
following heavy rains. As recently as May 1988, 40,000 gallons of 
phosphoric acid were accidentally released into the Alafia River causing 
a major fish kill. In the case of power plants, entrainment losses to 
fish populations have been judged to be acceptable once units are 
equipped with fine mesh screens. The cumulative loss at plants not yet 
equipped with screens needs to be addressed. Without a better 
understanding of how these fish populations function, it is virtually 
impossible to assess the ultimate consequences of continued or increased 
entrainment of the early life stages. Much progress has been made toward 
controlling industrial impacts upon Tampa Bay, but much more work remains 
to be done. 


168 



LITERATURE CITED 


Blakey, A.F. 1973. The Florida Phosphate Industry: A History of the 
Development and Use of a Vital Mineral. Harvard Univ. Press, Cambridge, 
MA. 197 pp. 

Fehring, W.K. 1985. History and development of the Port of Tampa, pp. 
512-524, In: S.F. Treat, J.L. Simon, R.R. Lewis, III and R.L. Whitman, 
Jr. (eds.), Proceedings, Tampa Bay Area Scientific Information Symposium 
(May 1982). Burgess Publ. Co., Inc., Minneapolis, MN. 663 pp. 

Florida Power Corporation. 1986. P.L. Bartow Power Plant. Entrainment 
and impingement monitoring program. Final Rept. 68 pp. 

Galtsoff, P.S. 1954. Gulf of Mexico. Its origin, waters and marine 
life. U.S. Fish & Wildl. Serv., Fish. Bull. 89. Washington, DC. 

Garrity, R.D., N. McCann, and J.D. Murdoch. 1985. A review of 
environmental impacts of municipal services in Tampa, Florida, pp. 526- 
550, In: S.F. Treat, J.L. Simon, R.R. Lewis, III and R.L. Whitman, Jr. 
(eds.), Proceedings, Tampa Bay Area Scientific Information Symposium (May 
1982). Burgess Publ. Co., Inc., Minneapolis, MN. 663 pp. 

Leverone, J.R. and S. Mahadevan. 1986. A study of the thermal effects 
on benthic communities in the vicinity of Big Bend, Tampa Bay. Tech. 
Rep. to Tampa Elec. Co. 50 pp. + Appendices. 

Lewis, R.R. and E.D. Estevez. 1988. The ecology of Tampa Bay, Florida: 
An estuarine profile. U.S. Fish & Wildl. Serv., Off. Biol. Serv., 
Washington, DC. 

Moon, R.E. 1985. Point source discharge in the Tampa Bay area. pp. 551- 
562, In: S.F. Treat, J.L. Simon, R.R. Lewis, III and R.L. Whitman, Jr. 
(eds.), Proceedings, Tampa Bay Area Scientific Information Symposium (May 
1982). Burgess Publ. Co., Inc., Minneapolis, MN. 663 pp. 

McNulty, J.K., W.N. Lindall, Jr. and J.E. Sykes. 1972. Cooperative Gulf 
of Mexico estuarine inventory and study. Florida: Phase 1, area 
description. NOAA Tech. Rept. NMFS CIRC-368. 

Phillips, T.D., J.M. Lyons, J.M. Daily and M. Sigurdson. 1977. A study 
of ichthyoplankton seasonality and entrainment by the Big Bend Power 
Plant, Tampa Bay, FL. pp. 5i-5-120, In: R.D. Garrity, W.J. Tiffany and S. 
Mahadevan (eds.), Ecological studies at Big Bend Steam Electric Station 
(Tampa Electric Co.): An analysis and summary of studies on the effects 
of the cooling water system on aquatic fauna, Vol. 3. 

Tampa Bay Regional Planning Council. 1983. Tampa Bay Management Study. 
Tampa Bay Reg. Plann. Council, St. Petersburg, FL. 130 pp. 


169 



Tampa Bay Regional Planning Council. 1985. The future of Tampa Bay. 
Tampa Bay Reg. Plann. Council, St. Petersburg, FL. Various pages. 

Tampa Bay Regional Planning Council. 1986a. Documenting the economic 
importance of Tampa Bay. Tampa Bay Reg. Plann. Council, St. Petersburg, 
FL. 143 pp. + appendices. 

Tampa Bay Regional Planning Council. 1986b. Ecological assessment, 
classification and management of Tampa Bay tidal creeks. Tampa Bay 
Regional Planning Council, St. Petersburg, FL. 147 pp. + appendices. 

Tampa Electric Company. 1980b. 1979 aquatic ecology program, Big Bend 

Station Unit 4. 142 pp. 

Weiss, W.R., E.P. Wilkins and D.N. Perkey. 1979. Final Rept. 
Entrainment and impingement monitoring program, A.W. Higgins Power Plant. 
Prepared for Florida Power Corp., St. Petersburg, by NUS Corp., 
Clearwater, FL. 177 pp. 


170 


PORTS AND PORT IMPACTS 


William J. Tiffany, III and David E. Wilkinson 
Port Manatee, Florida 


INTRODUCTION 


The purpose of this paper is to familiarize the reader with one of 
the major influences on this region, collectively the ports and their 
attendant impacts. 

Of the 14 deepwater seaports in Florida, 3 are located on Tampa 
Bay (Figure 1). There are no commercial ports on Sarasota Bay. Although 
this discussion will center on these ports, specifically the Port of 
Tampa (Florida’s largest port), Port Manatee (4th largest), and the 
smaller Port of St. Petersburg, keep in mind that there are many other 
maritime commercial and recreational activities and centers in both Tampa 
and Sarasota Bays which exert a significant impact on the local 
environment. Some of these include the many marinas and private docks 
which dot the waterfront, commercial fishing docks, and several large 
private terminal facilities such as those operated by power companies 
which bring in oil and coal for generating electricity. Certainly these 
operations all have similar potential for impacting the environment, as 
do the major ports (Phillips et al. this report). All have a potential 
for spills, use channels and landside facilities which were created at 
some expense to the environment, and, in some ways, have a greater impact 
than the actual port facilities. For example, Estevez and Merriam (this 
report) discuss the typical shoreline of Sarasota Bay and its extensive 
alteration for water related activities. At the recent Sarasota Bay Area 
Scientific Information Symposium (SARABASIS), it became readily apparent 
that recreational boat traffic and navigation congestion problems con¬ 
stitute significant concerns to Sarasota area residents. 


HISTORICAL OVERVIEW 


The ports of Tampa Bay have evolved from a long history of 
maritime commerce that dates back to the Post Columbian era, when Cuban 
fishermen utilized the vast resources of Tampa and upper Sarasota Bays to 
supply their growing population with a source of protein-rich food. It 
was not until after Florida’s statehood in the 1850’s, just prior to the 
Civil War --when Tampa farmers started shipping cattle to Cuba-- that the 
Cuban fishing industry faded. By this time, Fort Brooke (a military post 
in the upper Bay system) was well established and provided protection 
from hostile Indians. A brisk maritime trade developed, serving the 
growing civilian communities around Tampa Bay, and it provided the only 
connection to other markets. 


171 





Figure 1. 


H)flJ amP PM Ba p e t t M ary i n °ni da (ada P ted from Lewis 1976; TBRPC 
1985). PM, Port Manatee; PS, Port of St. Petersburg; PT, Port 
of Tampa; SS, Sunshine Skyway Bridge. 


172 











In the late 1800’s an event occurred which would forever change 
the Bay area. Phosphate was discovered in ancient Pliocene deposits 
along rivers and underground throughout the region. Mining operations 
rapidly expanded to strip the region of its valuable mineral deposits, 
and in fact the growth and competition which accompanied this new 

industry rivalled the 1840’s gold rush in size and in notoriety. 
Regardless, this singular discovery would eventually change the entire 
economy of the region, and with it the actual physical nature of 

Southwest Florida as we know it today. This would be accomplished not 
just through mining operations themselves, but through the physical 

changes imposed on shoreline shipping communities such as Tampa and its 
relatively pristine Bay ecosystem. By 1908 when the first large vessels 
entered Tampa Bay to haul phosphate rock out, the die was cast for 

physical alterations to the entire Bay system. To illustrate the impact, 
it is necessary to discuss phosphate very briefly. 

Twenty percent of the world’s phosphate production and 80% of all 
United States phosphate output takes place just east of Tampa and 

Sarasota Bays (Florida Phosphate Council, personal communication). 
Approximately 50% of all tonnage leaving Tampa Bay is composed of 

phosphate related products. Even though this is down from 80% just 10 
years ago (primarily due to expanding foreign sources and a depressed 

fertilizer market), it still makes the Port of Tampa alone one of the top 
10 ports tonnage-wise in the United States. By comparison, the ports of 
New Orleans and Houston may be far greater in physical size; but 

considered as a whole, the ports of Tampa Bay together are now the 4th 
largest in the country in terms of both tonnage and vessels called to 
port (Florida Ports Council, personal communication). Last year alone, 
these ports handled over 50 million tons of waterborne commerce -- more 
than any other port in the southeastern United States. 

As one looks at the 70-some miles of 43 foot deep channel 
traversing the Bay (Figure 1), keep in mind that its initial development 
was almost exclusively related to phosphate trade and the need for deeper 
channels to allow deep-draft ocean-going vessels to navigate. Although 
petroleum (and its related products) is a major maritime cargo and is the 
principal incoming product to Tampa Bay, it is historically a distant 
second-runner in use of the channels compared to phosphate products. 
Other major cargoes include cement, coal, animal feeds, scrap metal, and 
lumber. Several cruise lines are also located in Tampa Bay ports. 

Before discussing the channels and port development impacts, 
mention of a quirk regarding the channel and its strategic importance for 
Tampa Bay is in order. Tampa Bay, and specifically Port Manatee, is the 
closest United States deepwater port to the Panama Canal. ALL large 
ships sailing in and out of Tampa Bay must use the main ship channel, and 
in turn, must pass under the Sunshine Skyway Bridge. Besides the 
significance this bridge has regarding circulation problems in the Bay, 
ironically this so-called Gateway to Tampa Bay can also be a closed gate. 
An act of war or a navigational error resulting in collision with the 
bridge (as occurred several years ago) can bring the bridge down into the 
channel, blocking all navigation in or out. In fact, contingency plans 


173 


exist to drop the main span purposely into the channel to prevent foreign 
intrusion, if necessary. The non-obstructed nature of the mouth of Tampa 
Bay has previously been considered a positive military advantage since 
the late 1890’s when Teddy Roosevelt and the Rough Riders sailed out from 
the Tampa docks on their voyage to Santiago. 

Dredged Material 

Due to the inherent shallow nature of Tampa Bay, dredging and 
filling activities are critical to all port operations, including 
continual development of port facilities onshore and on bay fill sites, 
the creation of additional channels for navigation, and the routine 
maintenance of existing channels and berth spaces. These activities have 
resulted in the dredging of more than 100 million cubic yards of material 
for the creation of the large port infrastructure alone. The United 
States Geological Survey estimates that no less than 13 square miles of 
Tampa Bay has been lost to dredge and fill activity (TBRPC 1985) 
(Figure 2). This does not include dredged spoil volumes generated during 
recent channel maintenance. As a result of the last federal dredging 
project which just ended, that figure amounted to over 70 million cubic 
yards. Presently the Corps predicts that the removal of another several 
million cubic yards will be required by Fiscal Year 1989. (For an 
historical chronology of dredging and filling projects which have 
resulted in the present system of channels and fill sites, the reader is 
referred to Fehring 1985; Goodwin 1984; Lewis 1976; TBRPC 1985; USCOE 
1983). 


Fehring (TBRPC 1985) classified dredged material disposal 
strategies in Tampa Bay into five general areas: ocean dumping, estuarine 
open-water disposal, estuarine habitat-creation disposal, estuarine 
confined disposal, and upland confined disposal. The reader is referred 
to that publication for a thorough discussion of the benefits and 
problems associated with each type of disposal. For the sake of brevity 
here, estuarine disposal will be presented as a single topic. 

Estuarine disposal of dredged material is now strictly regulated 
by numerous governmental agencies through an elaborate permitting system 
(predominantly administered by the United States Army Corps of Engineers 
and the State of Florida Department of Environmental Regulation). 
Unconfined estuarine disposal is no longer considered a viable method, 
due to water quality problems and the destruction of benthic habitat (see 
Lewis 1976; and previous papers in this report which address water 
quality, circulation, and biology). 

All three of Tampa Bay’s ports have evolved on dredged and filled 
coastal habitats. For example, although Port Manatee’s beginnings were 
conceived on highly altered coastal lands already used for agriculture, 
the spoil generated from dredging the basin and berthing slips was 
fortuitously placed waterward to create more land for port development 
(Figures 3 and 4). Related channel dredging resulted in a spoil island 
created from large rock and sand materials, while fines and sand were 
placed landward (discussed later). Even more dramatic is the filling 


174 






Figure 2. Areas of Tampa Bay dredged or filled for port development, 
past 100 years (adapted from Fehring 1985). 


175 






























176 


Figure 3. Port Manatee Construction, 1969. Dragline building phase dike adjacent to cleared shoreline 
Dredged material will be pumped behind dike to extend land seaward. 






177 


Figure 4. Fort Manatee, 1981 






that has taken place in the upper Bay system during the creation of the 
Port of Tampa and its channels (Figure 2). The filling which resulted in 
the formation of Davis Island alone covered over 800 acres of Bay bottom, 
including productive intertidal marshlands, and that is only a fraction 
of the fill placed in Tampa Bay estuarine waters. Recently the Port of 
Tampa --in conjunction with the United States Fish and Wildlife Service-- 
completed a mitigation study for Tampa Bay (Dial and Deis 1986) with the 
intention of ameliorating some of the problems of past dredging and 
filling activities conducted by all Tampa Bay ports and by other coastal 
developers. Likewise, the Tampa Bay Regional Planning Council has 
prepared a report (TBRPC 1985) which includes recommendations for 
corrective action in the Tampa Bay area. 

Besides shoreline fill in the bay, numerous spoil islands have 
also been created (Figure 5). Most of these islands follow the ship 
channels for the obvious reason of disposal ease. Some of the older 
islands were not properly banked or diked and are eroding badly (e.g. the 
Hillsborough Bay spoil islands). Besides causing water quality problems, 
erosion is also contributing to the re-silting of the channels. Other 
islands, including older submerged spoil piles, are likewise eroding 
badly (particularly those paralleling Port Manatee’s cut -- especially 
during northwesterly storm fronts). 

However, if constructed and managed properly, spoil islands can 
have beneficial uses other than to provide future development sites. For 
example, many spoil islands in Tampa Bay are well documented breeding 
sites for numerous species of birds. Sarasota Bay, likewise, has many 
spoil islands along its Intracoastal Waterway which serve as rookeries 
for many birds including brown pelicans. The completion of the West 
Coast Inland Waterway in 1967 (Intracoastal Waterway) which runs north 
from Ft. Myers through Sarasota and Tampa Bays resulted in the removal of 
over 14 million cubic yards of material (West Coast Inland Navigation 
District, personal communication). The 100 foot wide channel, which is 
more than 150 miles in length, is replete with numerous spoil islands. 
It was suggested at the recent Sarasota Bay Symposium (Estevez 1988) that 
proper management and restoration on these islands could be a viable way 
to recover historic habitat lost through coastal development. This 
reiterates management objectives established by New College students 
during their study of spoil islands in Sarasota Bay several years ago 
(Carlson 1971). 

Upland disposal of port spoil material in the Bay area is quite 
limited at this time. One of the largest and most notable sites used to 
contain spoil material generated during maintenance dredging is located 
at Port Manatee. Being a relatively land-rich port, Manatee has 
committed to contain all maintenance dredged spoil upland. Considering 
the spoil material as a resource, Port Manatee has designated over fifty 
acres of the disposal site for development of a finfish hatchery by the 
State of Florida Department of Natural Resources in conjunction with the 
Mote Marine Laboratory (Haddad, this report). 


178 



179 


Figure 5. Spoil island construction, Tampa Bay. Hydraulic dredge purrping fill material onto incipient 
spoil island during creation of channel. Note boundary lines established for spoil disposal 
site. Wide interrupted line indicates centerline of channel. 



An example of poor upland disposal is the Hendry site just south 
of Port Manatee. Dredged spoil was indiscriminately pumped into prime 
tidal creek habitat with the intention of creating an upland development 
site. Although the State of Florida extracted fines and much of the 
filled land from the owner (who was also the party responsible for the 
filling), much of the tidal creek system is lost forever. During the 
past three years Port Manatee has worked closely with several 
governmental and private agencies on the Hendry site, involving numerous 
environmental projects specifically aimed at restoring circulation to 
tidal areas, replanting coastal marshes, and transplanting seagrasses 
offshore to provide nursery habitat. 

Considering spoil disposal, by far the most controversial method 
has been open ocean dumping. The United States Environmental Protection 
Agency has designated a general disposal area in the Gulf of Mexico west 
of Tampa Bay for dredged material. Specific dump sites used recently are 
located within this area approximately 13 and 18 miles, respectively, 
from the coast. Although this method is accepted by many as the primary 
method for disposal of material generated during maintenance dredging of 
the navigation channels in Tampa Bay, it is certainly not without impact 
(see Pequegnat et al., 1981 for a review of general impact analysis 
procedures regarding ocean disposal sites). 

Numerous surveys and impact studies have been conducted in an 
attempt to locate suitable disposal areas off of Tampa Bay, but problems 
with specific sites persist (Amson 1984). Much of the controversy 
surrounding the disposal operations and site selection deals with the 
potential for disturbing emergent hard-bottom communities. Even if 
suitable sandy substrates are chosen (with the acceptance that benthic 
communities will be smothered), it is possible that off-site impacts can 
occur, depending on natural currents, storms, dumping at incorrect 
coordinates, etc. 

During the recent Tampa Harbor Deepening Project, the vast 
majority of dredged material was transported offshore for ocean disposal. 
Before the end of Fiscal Year 1989, several million cubic yards of 
additional spoil are slated for ocean disposal (United States Army Corps 
of Engineers, personal communication). 

Spill Considerations 

As was previously mentioned, the second largest tonnage cargoes in 
Tampa Bay are oil and petroleum related products. Considering the heavy 
traffic in this commodity, it is quite surprising that Tampa Bay does not 
regularly experience major oil spills -- defined by the National Oceanic 
and Atmospheric Administration to be greater than 100,000 gallons (N0AA 
1985). In fact, Tampa Bay has one of the lowest incidents of spills of 
any Gulf port community. This is not to say that Tampa Bay has not had 
its share of oil spills; many of these are not port related but are 
attributable to power plant fuel shipments. On the average there are 
between 100-150 spills per year reported to the 7th Coast Guard District 
(United States Coast Guard, personal communication). These spills are 


180 



typically less than 100 gallons and average 30-40 gallons. This is 
certainly nothing compared to the Amazon Venture and her 800,000 gallon 
spill off Georgia in 1986, or compared to the problems the Port of 
Jacksonville has had with numerous recent large spills in excess of 
10,000 gallons. 

Tampa Bay does, however, experience many small spills into open 
waters which are commonly known as "mystery spills" (usually occurring at 
night, away from lay berths, and not traceable). These incidents usually 
involve the intentional pumping of bilge slops and are the most difficult 
to deal with because they almost always end up onshore with disastrous 
results. In these cases, cleanups are difficult and costly (not to 
mention the cost to the environment). 

Dockside accidental spills are much more common than accidental 
open water spills and occur most of the time through human error, 
predominantly involving a failure to connect and disconnect hoses 
properly (Figure 6). When a spill does occur, cleanup can be effected 
fairly easily by booming off the site and using absorbent pads and 
snorkel trucks to pick up the residual. All Florida ports are now 
empowered under Florida State law (Chapter 16B-16.04, Florida 
Administrative Code) to have functional Discharge Cleanup Organizations, 
which are licensed by the Florida Department of Natural Resources, and 
which should be capable of containing and cleaning up all spills that 
occur in port. Most ports belong to cleanup cooperatives formed by the 
port authority and the port tenants, who in turn, hire professional 
third-party contractors, licensed and bonded by the State and Coast Guard 
to perform cleanup and disposal activities. 

The National Oceanic and Atmospheric Administration indicates that 
more than 5,000 vessel trips per year occur in and out of the ports on 
Tampa Bay (N0AA 1985). Shipping routes from Tampa Bay extend throughout 
the Gulf of Mexico and thence worldwide. As one might anticipate, there 
are attendant petroleum discharges all along these routes. These 
discharges are defined as "operational" discharges to be polite, but they 
are really intentional (usually involving bilge pumping and tank 
cleaning). These routine, intentional discharges contribute 30 times 
more oil than all the accidental spills combined for the entire Gulf of 
Mexico (NOAA 1985). Worldwide this practice amounts to 571 million 
gallons annually. Until recently this was an accepted practice, but with 
the adoption of the new International MARPOL regulations (see Federal 
Register Vol. 50, No. 174:36768-36795), which now require shorebased rec¬ 
eption facilities to be available for the pumping of bilge slops, it is 
expected that these figures may be significantly reduced. 

Future Directions 


Probably the single most significant event to take place in recent 
years which will have a positive effect on port operations in Tampa Bay 
(and in other Florida ports, as well) is the newly passed Local 
Government Comprehensive Planning and Land Development Regulation Act 
(Chapter 163, Florida Statutes; Chapter 9J-5, Florida Administrative 


181 




Figure 6. Dockside transfer of petroleum products. 


182 




Code). This Act lays the ground rules for comprehensive long range 
planning for future growth in Florida. The sections of the Act which 
most directly affect ports are the Coastal Management Element and the 
Port Element. As this Act applies specifically to ports on Tampa Bay, it 
requires completion of Comprehensive Master Plans by the end of 1988. 
These port Master Plans will in turn be incorporated as elements of each 
local government’s Comprehensive Growth Plan, and more importantly, the 
port plans must be consistent with state mandated standards and criteria 
as spelled out in the Coastal Management Element and the Port Element. 
The ultimate goal is "to promote the orderly development and use of 
ports" (Chapt. 163, F.S.). 

Some of the specific items for which each port will be responsible 
are as follows: 

1. Drainage and the impact of non-point and point source 
pollution on estuarine water quality must be covered. This 
basically will entail the development of master drainage 
and stormwater management plans. 

2. Existing natural shorelines are to be protected. 

3. Natural systems Inventories will be required, with the 
intention of developing land use guidelines which protect 
or enhance existing resources. 

4. An analysis of environmental, socioeconomic, and fiscal 
impacts of development and redevelopment will be required. 

5. Contingency plans will be required for any natural 
disasters such as hurricanes, and for man induced hazards 
such as spills and fires. 

All of these items and numerous others will then be subjected to 
extensive local, regional and State review before adoption by local 
ordinance. 

The development of the Coastal Management Element was a major 
priority of the Governor’s office and the Florida Department of Community 
Affairs. This fact is reflected in the requirements for this element, 
which are considerably more detailed and far reaching than those for any 
other elements of the Act. 

In closing, most Florida ports and certainly all three deepwater 
ports on Tampa Bay already have begun to shift emphasis away from some of 
the problematic cargoes that have been pollution problems. Admittedly, 
the reasons are more economic than philanthropic; nevertheless, the 
concept of increased diversity in cargo means healthier financial systems 
and usually fewer environmental problems. As the ports are increasingly 
being adversely affected by slumps in much of the bulk cargo industry 
(especially phosphate products), many new items related to the food 
industry are being added. In particular, orange juice, frozen beef, and 
bananas now traverse Tampa Bay waters on a regular basis. The ports are 
also handling many new products related to the construction industry such 
as raw lumber, finished wood items, pipe, and cable. One of the newer 
developments to be exploited is in the area of containerized cargo. 


183 


As West-Central Florida continues to grow, the ports of Tampa Bay 
will continue to develop their cargo mixes accordingly. Concurrently the 
ports will expand as a result of increased maritime commercial 
activities. With adequate comprehensive master plans in place, many of 
the historical adverse impacts of port growth and development can be 
avoided. 


184 


LITERATURE CITED 


Amson, J.E. 1984. Monitoring of an ocean dredged material disposal 
site. In: R.L. Montgomery and J.W. Leach (eds.), Dredging and Dredged 
Material Disposal, Vol. 1. Amer. Soc. Civil Eng., New York, NY. 

pp. 601-608. 

Carlson, P.R. (ed.). 1971. Patterns of Succession on Spoil Islands: A 

Summary Report. New College Environ. Stud. Prog., Sarasota, Fla. 
114 pp. 

Dial, S.R. and D.R. Deis. 1986. Mitigation options for fish and 
wildlife resources affected by port and other water-dependent 
developments in Tampa Bay, Florida. U. S. Fish Wildl. Serv. Biol. Rep. 
86(6). 150 pp. 

Estevez, E.D. (ed.). 1988. Proceedings, Sarasota Bay Scientific 

Information Symposium (1987). In press. 

Fehring, W.K. 1985. History of the Port of Tampa, In: S. Treat, J.L. 
Simon, and R.R. Lewis (eds.), Proceedings, Tampa Bay Area Scientific 
Information Symposium. Bellwether Press, Tampa, Fla. pp. 512-524. 

Goodwin, C.R. 1984. Changes in tidal flow, circulation, and flushing 
caused by dredge and fill in Tampa Bay, Florida. U.S. Geol. Surv. Open 
File Rep. 84-447. 

Lewis, R.R., III. 1976. Impact of dredging in the Tampa Bay estuary, 
1876-1976, In: E.L. Pruitt (ed.), Proceedings of Second Annual Conference 
of the Coastal Society. Coast. Soc., Arlington, VA. pp. 31-55. 

NOAA. 1985. Gulf of Mexico Coastal Zone Strategic Assessment: Data 
Atlas. U.S. Govt. Print. Off., Washington, D.C. Maps 1.0-6.07. 

Pequegnat, W.E., L.H. Pequegnat, B.M. James, E.A. Kennedy, R.R. Fay, and 
A.D. Fredericks. 1981. Procedural guide for designation surveys of 
ocean dredged material disposal sites. USC0E Tech. Rep. EL-81-1. 

268 pp. 

TBRPC. 1985. The Future of Tampa Bay. Tampa Bay Regional Planning 
Council. St. Petersburg, Fla. 263 pp. 

USCOE. 1983. Manatee Harbor, Florida: General Design Memorandum. 
USCOE, Jacksonville, Fla. 50 pp. 


185 



RESOURCE STATUS AND MANAGEMENT ISSUES 
OF SARASOTA BAY, FLORIDA 


Ernest D. Estevez 
Mote Marine Laboratory 
Sarasota, Florida 

John Merriam 

Department of Natural Resource Management 
Sarasota County 


INTRODUCTION 


Sarasota Bay is a small, subtropical embayment on the west coast 
of peninsular Florida. It is connected to the Gulf of Mexico and to the 
southern end of Tampa Bay via Anna Maria Sound. Like much of coastal 
Florida, the Sarasota Bay area is experiencing rapid population growth, 
although most of its development having adverse environmental impact has 
occurred only in the last 50 years. Barrier islands between the bay and 
gulf are completely developed as residential, light commercial, and 
tourist areas. Nearly the entire upland watershed of Sarasota Bay is 
also developed, mostly as suburban residential and commercial areas. 
There are no heavy industries in the watershed, and the amount of 
agricultural land is low and decreasing due to urbanization. The local 
economy is driven primarily by retirees, tourism, and the services 
industry which have developed because of the bay, warm climate, and 
historical circumstances. The bay supports an extensive recreational 
industry and is showing signs of overuse. For all practical purposes, 
there has been little more than a century of modern settlement in the bay 
area, with 3 periods of major development (the Florida land boom of the 
1920’s; the post World War II boom; and the present "sunbelt" period of 
population growth.) 

The bay and its watershed are situated equally in Manatee and 
Sarasota Counties (Figure 1). The combined population of these counties 
was 420,500 people in 1986 (Collins 1988). The largest cities --and 
county seats-- are located near the bay at Bradenton and Sarasota, in 
Manatee and Sarasota Counties, respectively. Bradenton Beach and the 
Town of Longboat Key are two small municipalities on the barrier island 
of Anna Maria and Longboat Key, respectively. Two other islands separate 
the bay and gulf south of Longboat Key (Lido, Siesta); Lido Key and a 
small portion of the northern-most tip of Siesta Key are within the city 
limits of Sarasota, and the balance or Siesta Key is part of 
unincorporated Sarasota County. Manatee County participates in the Tampa 
Bay Regional Planning Council, whereas Sarasota County is a member of the 
Southwest Florida Council, meaning that Sarasota Bay is divided across 
the middle into two separate planning bodies. Both counties and the 
whole bay are within the Manasota Basin of the Southwest Florida Water 
Management District and the Southwest District of the Florida Department 
of Environmental Regulation (Sauers and Patten 1981). 


186 




Figure 1. Sarasota Bay and surrounding inshore waters. 


187 










































Resource Description 


Sarasota Bay has been called a lagoon, a neutral estuary, and a 
bay. It is located between Tampa Bay and Charlotte Harbor, the nation’s 
17th and 18th largest estuaries, respectively (Seaman 1988). It 
exemplifies a number of water bodies along the Florida and gulf coasts by 
its proximity to open, shallow waters; much greater width than depth; 
physical dominance by wind and tides rather than tributaries; and 
recreational uses (Estevez 1988). 

The bay area has a mean annual temperature and rainfall of 72.0°F 
and 54.6 inches of rain per year. Most of the rain (60%) falls between 
June and September (Walton 1988). The bay is approximately 20 miles long 
and has a mean depth of 5 ft. Deeper portions of the bay’s central basin 
are 8-10 ft deep, and Longboat Pass (between Longboat Key and Anna Maria 
Island) has a maximum depth of 27 ft. Extensive shallow areas bordering 
the bay are mudflats, seagrass beds, or wetlands. The bay is subject to 
a relatively low energy climate (Evans 1988). Winds vary to and from the 
gulf, except during winter frontal systems when northwest winds prevail. 
Tides are mixed diurnal and semidiurnal, with a mean and extreme range of 
1.3 and 2.1 ft, respectively (Goodwin 1988, Walton 1988). Average wave 
heights (on barrier beaches) are about 1 ft, and sediment transport is 
minimal (Evans 1988, Harvey 1982). 

Currents in the bay are tide and wind dominated, ranging between 
0.3ft/sec in open bay areas to 1.5 ft/sec within inlets. A nodal area-- 
or zone of little net water movement-- crosses the mid bay area in 
Manatee County (Walton 1988). Flushing time for the bay in general is 
estimated to be 2-15 days, although actual rates depend upon freshwater 
inflow (DeGrove and Mandrup-Poulsen 1984; Dendrou, Moore and Walton 
1983). Toward the east and north the bay’s watershed is bounded by the 
Braden and Manatee Rivers, respectively, which flow into Tampa Bay. 
Uplands within the watershed occupy twice the surface area (80 sq mi) of 
open bay waters (40 sq mi) and are drained by the Palma Sola, Bowlees 
Creek, Whitaker Bayou, Hudson Bayou, and Phillippi Creek basins. The 
Phillippi Creek basin is the area’s largest. Its impervious area 
increased from 15% in 1966 to 22% in 1988 and is expected to reach 24% by 
the year 2000. This trend is believed applicable for the watershed as a 
whole. Combined peak discharge of nonpoint sources to the bay area are 
about 13,560 cfs (for a 25 year, 24 hr event over the entire watershed) 
(Flannery 1988, Giovannelli 1988). Treated wastewater contributes another 
15-25 cfs, and there are no industrial discharges of consequence. 

Water quality is considered "good" for most parts of the bay*. In 
fact, all waters of the bay except for two small creek mouths are 


According to 305b summaries by the Florida Department of 
Environmental Regulation, using water quality (marine) and trophic state 
(aquatic) indices. 


188 




designated by the state as Outstanding Florida Waters, which provides for 
strict limits to degradation (Florida Department of Environmental 
Regulation 1986). Incomplete nutrient and other data suggest a general 
trend of improvement and a decline in salinity which has been most 
evident along the mainland shore. Urban stormwater runoff has been 
implicated as the cause for reduced salinities (Heyl and Dixon 1988). 
Areas of "fair" water quality include the bayside waters of Longboat Key, 
Little Sarasota Bay, and Phillippi Creek. Whitaker Bayou has fair to 
"poor" water quality because of stormwater and the City of Sarasota’s 
municipal wastewater treatment plant effluent. An area of about 210 
acres in the bay is directly affected by Whitaker Bayou discharges 
(Figure 2), and the area of indirect effects is probably ten times larger 
(Pierce and Brown 1986, Fortune 1985). 

Direct and indirect effects of dredging and filling have not been 
evaluated with respect to water quality but are considered serious. Some 
beaches on all islands have been nourished at least once. Longboat and 
New Passes have been dredged for navigation purposes. The Intracoastal 
Waterway definitely caused several areas of bay-bottom to be spoiled; may 
be responsible for large losses of seagrasses in the north bay due to 
indirect turbidity effects; and is believed to have caused or enhanced 
closure of Midnight Pass (in Little Sarasota Bay, between Siesta and 
Casey Keys) (Sarasota County 1984). Major residential and commercial 
filling projects have been conducted on Bird, Lido, and Longboat Keys and 
City Island. These combined projects have altered circulation, tidal 
prisms, fine sediment budgets, inlet stability, bay transparency, and 
other parameters. 

The primary producers of Sarasota Bay are phytoplankton, 
seagrasses, macroalgae, and wetlands (marshes and mangrove forests). The 
system is converting from a phytoplankton-dominated one with significant 
contributions (of carbon fixation, habitat, etc.) by the other producers, 
to a more simplified system dominated by phytoplankton without these 
other producers (Steidinger and Phillips 1988; Lewis 1988; Evans and 
Evans 1988). Sarasota Bay and nearby waters are regularly affected by 
naturally occurring dinoflagellate blooms known as red tides. These 
blooms originate far offshore but may be perpetuated by inshore nutrient 
enrichment. Red tides defaunate affected areas of the bay and inhibit 
tourism (Habas and Gilbert 1974). During summer months local 

phytoplankton blooms also kill fish in canals. 

There are four seagrass species in the bay; all grow in water less 
than 6-7 ft deep. Between 1948 and 1979 there was a 54% decrease in 
seagrass cover along the eastern bay; a 65% loss around New Pass; and an 
83% loss around Whitaker Bayou (Sauers and Patten 1981). Baywide losses 
are estimated to be 20-30 percent (Figures 3 and 4) (Steidinger and 
Phillips 1988). Causes of these losses are not definitely known, but 
mineral turbidity (from beach, inlet and ICW dredging) and organic 
turbidity (from STP effluents) are suspected. Marshes are naturally rare 
in the bay, but three species of mangroves grow along protected 
intertidal shorelines instead. Forests have been ditched for mosquito 
control and filled for upland development. Bay shorelines have been 


189 



190 


Figure 2. Isopleth map of coprostanol concentration, ng/g dry sediment. 

















TAMPA BAY 


ANNA 
MARIA 
SOUND 

=r) 



Figure 3. Seagrass distribution in Sarasota Bay in 1957 (from Lewis 
1988a). 


191 



















Figure 4. Seagrass distribution in Sarasota Bay in 1986 (from Lewis 
1988a). 


192 











altered five-fold since 1948, mostly by bulkheading and invasion of two 
exotic tree species (Evans and Evans 1988). 

Shallow, protected waters and once-widespread seagrasses supported 
an abundance of shellfish, sport and commercial fishes and unique 
vertebrate species. The shellfish resources of the bay were based on 
hard clams, oysters, and scallops (Estevez and Bruzek 1986). Scallops 
have disappeared from the bay, not having been landed commercially since 
1964. Oyster landings ended in 1967 and hard clam landings ended in 
1971, but both are still present in the bay, and there are probably 
enough hard clams to support a renewed harvest (Figure 5). Actual 
harvesting would be limited to 2 areas conditionally approved by the 
state for adequate sanitation (Palma Sola Bay^; Longboat Key bayside) 
unless pollution abatement allowed new areas to be opened. 

Blue crab, stone crab, and (pink) bait shrimp are also taken from 
the bay (Stevely, Estevez and Culter 1988). There are 153 commercial 
blue crab permits and 180 stone crab permits issued for the two county 
area. Blue crab landings show marked, continual declines from 177,000 
lbs/yr in the 1950’s to about 30,000 lbs/yr today. Overfishing and 
habitat loss are believed responsible for the decline. Stone crab 
landings (of claws only) have increased from 6,400 lbs/yr to 24,000 
lbs/yr over the same period due to increased demand. Bait shrimp 
landings have fallen precipitously, causing some to regard the fishery as 
completely collapsed -- but this may be an artifact of reporting 

(Stevely, Estevez and Culter 1988). Some commercial bait fishing 

currently occurs in the bay. 

Sarasota Bay’s finfish resources are mullet (commercial only), red 
drum and spotted seatrout (commercial and sport), and snook (sport only) 

(Edwards 1988). Mullet represents the largest fishery, with 2 to 6 

million lbs landed annually. Whole fish are sent to local markets and 
manufacturers of fish products. Mullet roe has become a major byproduct, 
shipped to oriental markets (Haddad 1988). There may be some decline in 
mullet landings, but trends are indefinite. Spotted sea trout landings, 
however, have fallen six-fold from 300,000 lbs/yr in the 1950’s, due to 
the destruction of seagrasses and probably overfishing. Red drum 
landings peak at about 200,000 lbs/yr and vary widely. In the 1980’s, 
landings have been near 50,000 lbs/yr. The status of red drum has been 
declining throughout Florida, and last year seasons were adopted for 
their protection. Snook is a highly prized sport fish for which there 
are no landing data, but concern over their diminishing number has caused 
the adoption of seasons, plus limits to size, gear, and catch. Declines 
in snook stocks are attributed to habitat loss and overfishing (Edwards 
1988). 


2palma Sola Bay has been closed since 1981 because of excess 
coliform from runoff and septic tank leakage. 


193 



Landings, in Pounds 





Figure 5. 


Sarasota County marine landings, 


1953 to 1981. 


194 













Unique or important vertebrates in Sarasota Bay include the 
Atlantic loggerhead turtle, bottlenose dolphin, and West Indian manatee. 
Sea turtles use barrier beaches for nesting. In Manatee and Sarasota 
Counties combined, about 1000 nests are established per year (Mapes 1983- 
1986). Their success depends on storms, natural predators, and beach 
management practices. Dolphin populations have been studied longer in 
Sarasota Bay than anywhere else in the world (Wells 1988). Dolphins 
probably use the bay as a breeding ground and their numbers are stable, 
which is in marked contrast to manatees, an endangered species. Manatees 
occur in Sarasota Bay during summer months and use the bay as a corridor 
prior to the cold season. Between 25 and 50 manatees are believed to 
inhabit the bay on this basis (Patton 1987). The animals are threatened 
most by high speed boat traffic. 

Sarasota Bay supports or enhances about 50 basic, water-dependent 
industries, institutions, and operations and about $20 million annually 
in overall payrolls (Daltry 1988). This direct benefit is augmented by 
an undocumented, indirect economic benefit and also by $115 million of 
economic value in the bay as a wastewater and stormwater receptacle. In 
addition, residential, waterfront property has an estimated value of $1.9 
billion. Close proximity to the bay (less than 2% of the two county land 
mass) results in property tax equal to more than 19% of the total two 
county tax base (Daltry 1988). 

Recreation constitutes the major use of the bay in the forms of 
boating, skiing, diving, surfing, fishing, sightseeing, and nature study. 
Sailing, especially regatta events, attract a national field of 
competitors. There are about 30,000 registered boats in the two county 
area, mostly pleasure craft. In 1985 there were almost 13 million beach 
use and saltwater fishing "occasions" in Manatee and Sarasota Counties. 
Such intensive contact and consumptive use represents a strong 
disincentive for pollution. A dozen conservation and environmental 
groups have a combined membership of nearly two thousand persons. The 
bay is used for educational purposes by one university, one community 
college, several high schools, and a marine program for youthful 
offenders. 

History of Settlement and Resource Management 

The Sarasota Bay area is urbanized in terms of its actual 
watershed, but the system is different than older, urbanized ones because 
it is recently settled and still has large areas of surrounding open 
space, farm land, and natural areas. The bay and basin have experienced 
only about 100 years of settlement. The period prior to World War II saw 
relatively little change in land or bay use, and environmental laws have 
been in effect for the past 15 years, so it was mostly during the period 
1945-1975 that significant alterations to the bay and upland occurred. 
Today extensive areas of the watershed support land uses first put there 
(except for pasture or open range). This situation means that 
infrastructure is not as complex, well developed, or permanent as in 
northern coastal areas, so changes in land use, storm drainage, sewerage, 
or shoreline conditions may be easier or less expensive to accomplish. 


195 



The proximity of undeveloped interior lands may also facilitate projects 
which benefit the bay. Sewage treatment, for example, may be easier to 
provide at inland sites where gross densities are an order of magnitude 
lower than along the coast. 

Today Sarasota Bay is more regulated than it is managed. 
Regulatory limits to projects with adverse impact exist at the federal 
and state level, but local regulation can be traced to public outcry in 
the 1960’s over expansion of Bird Key and destruction of mangrove forests 
on the bay side of Longboat Key by a real estate development company. 
Local regulations were adopted to limit similar projects and to establish 
waters in the City of Sarasota as a marine park. Since then, the 
regional water management district has implemented rules controlling 
runoff and surface water management projects, and the state has (through 
the Department of Environmental Regulation - DER) enforced legislative 
acts addressing nonpoint and wastewater treatment levels. Most recently, 
in 1985 the Environmental Regulatory Commission designated Sarasota Bay 
as an "Outstanding Florida Water" (OFW), bringing into play the severest 
effluent regulations that are currently available in the state. 
Basically, OFW status requires that the DER issue no permit which 
directly lowers existing ambient water quality or indirectly degrades the 
OFW. However, the OFW status does not provide a management framework for 
the water body, even where water quality issues are concerned. It is 
merely a single regulatory criterion used in the issuance of permits. 

There have been several steps leading toward a management program 
for Sarasota Bay. In 1985 the state legislature passed the Local 
Government Comprehensive Planning and Land Development Regulation Act, 
creating a new coastal management section in state law. The law was 
amended in 1985-86 and requires local governments to address specific 

plan topics; coordinate plans with neighboring governments; and be 
consistent with regional plans. Special effort must be made to ensure 
that "certain bays, estuaries and harbors that fall under the 
jurisdiction of more than one local government are managed in a 

consistent and coordinated manner". These requirements may set the stage 
for bay management, but revised plans alone will not contribute to a 

comprehensive program unless (1) the bay is viewed in its entirety by 

each plan; (2) the process leads to an institutional advocacy for the 
bay; and (3) each plan adopts the same language relative to the bay. 
These final measures are not required by state law, and the extent to 
which planning efforts would be redirected to achieve them remains to be 
seen. 


Another significant advancement for Sarasota Bay’s management can 
be traced to the 1982 Tampa Bay Scientific Information Symposium, at 
which existing knowledge about that bay was reviewed and evaluated for 
management purposes. The symposium led rapidly to a series of work 
groups culminating in an Agency on Bay Management within the Tampa Bay 
Regional Planning Council. The Agency adopted a management plan for 
Tampa Bay (Tampa Bay Management Study Commission 1985), and it is in its 
second year of implementation. Success in the Tampa Bay setting 
encouraged scientists and resource managers to meet in 1986 to assess the 


196 


need for a management program for Sarasota Bay. The 1986 workshop 
recognized the value of such a program and endorsed a public symposium 
similar to that held for Tampa Bay (Estevez 1987). The symposium, known 
locally as SARABASIS 3 was held in 1987, and written proceedings will be 
available in 1988. Material from SARABASIS has been distilled for use by 
local planning agencies in preparing state-mandated comprehensive plans. 
Late in 1987 an estuarine seminar was held in Washington, D.C. on Tampa 
and Sarasota Bays under the sponsorship of the National Oceanic and 
Atmospheric Administration; SARABASIS materials also aided in preparation 
for that seminar and these proceedings. 

In 1987 the 100th Congress reauthorized the Water Quality Act, 
which contained a part (Section 320. National Estuary Program) 
instructing the Environmental Protection Agency (EPA) to identify and 
protect nationally significant estuaries and to encourage development of 
comprehensive conservation and management plans. The Act states that the 
Administrator of the EPA is to give priority consideration to 12 coastal 
systems including Sarasota Bay. The Governor of Florida formally 
nominated Sarasota Bay to the EPA in May 1987, and in July 1987 Florida 
and EPA entered into a State/EPA agreement by which the EPA and DER 
continued the nomination process for inclusion of Sarasota Bay in the 
National Estuary Program (NEP). In July 1988 Sarasota Bay was designated 
by the Administrator of EPA as a component of the NEP. 


PROBLEM IDENTIFICATION 


A total of 120 resource management problems and issues were 
identified from historical references, workshop and conference 
proceedings, local government plans, and other sources. As used here, 
"problems and issues" are in reference to both the causes of management 
concerns (such as nutrient enrichment) and also the symptoms or effects 
such concerns can take (such as algae blooms). In most cases the 
problems can be identified but not described or detailed. Indeed, the 
inability to understand the specifics of an issue contributes to the 
problem. 

Problem descriptions can only be developed once they are ranked by 
importance and studied in greater depth. This process is part of a NEP 
Management Conference but would also occur in a non-federal management 
initiative. In either case, key questions to address in the process of 
problem review will include (1) is the perception of the problem 
accurate; (2) does the problem influence a large part of the estuary; 
(3) can the likely cause of the problem be identified; and (4) is it 
feasible to correct the problem? 


3 for Sarasota Bay Area Scientific Information Symposium. 


197 






The 120 individual problems and issues are organized in Table 1 
into a few condensed sets and arranged with respect to management 
complexity. Criteria used for the sets and arrangements were (1) overlap 
with other problems; (2) extent to which problem concerns the cause of 
many other problems; (3) responsiveness to local needs; (4) the degree to 
which a problem is unique to the area, or is of national significance but 
may be easier to address in the Sarasota Bay area because of other 
circumstances; and (5) the probable role of federal, state and/or local 
government involvement. 

The sets are arranged from most federal involvement to most local 
involvement in Table 1. No priorities are implied by the order of sets 
within each level. Sets are meant to be organizing concepts around which 
management projects can develop, assimilating a number of specific, 
related problems in the process. Not all specific problems can be 
addressed by the sets described below, but refinement of the approach 
should improve such coverage. 


SUMMARY AND CONCLUSIONS 


Sarasota Bay was identified in Section 320 (National Estuary 
Program) of the Water Quality Act of 1987 for priority consideration as 
an estuary of national significance. The bay is the only Florida system 
so identified and the only subtropical one. It is a very small, 
relatively clean system which ranks poorly where estuarine area or number 
of major problems are considered. On the other hand, it ranks highly in 
terms of preservation need and in terms of its vulnerability because of 
its small size. It is also distinguished by having more problems 
resulting from development and overuse than from pollution, especially 
the many forms of pollution which plague northern estuaries. In this 
regard, Sarasota Bay represents an excellent setting in which to develop 
and evaluate management tools focusing on development and overuse 
impacts. The small size of the bay is an added advantage in such a 
context. Overall, Sarasota Bay offers the opportunity to address 
nationally significant problems such as integrated beach/inlet/channel 
maintenance, nonpoint source control, habitat loss, and sea level rise. 
Results from a Sarasota Bay study would also be transferable to similar 
lagoons, bar-built estuaries, and small embayments throughout the gulf 
and south Atlantic coastlines. Extensive tourism and seasonal residence 
of northern and midwestern visitors would extend the benefit of a local 
bay educational program to areas of the nation lacking bay management 
programs. 


198 



Table 1. 


continued. 


Table 1. Major Problem Sets for Sarasota Bay, in Order of Management 
Complexity. No priorities are intended by the order of listed 
items. 

A. Federal, state, regional and local participation 

These problem sets would benefit from a significant level of federal 

participation in addition to state, regional and local involvement. 

1. Stormwater runoff. The watershed is mostly developed and 
programs to retrofit existing developed areas will be 
complicated and costly. Stormwater is a serious problem 
in the bay, but improvements to runoff management systems 
should be measurable in terms of bay resources and 
values. Response to runoff projects will be easier to 
detect than in systems facing multiple stresses. Studies 
of runoff in tidally affected creeks would be nationally 
significant. 

2. Beach/inlet/channel management. At present, beaches are 

(or can be) nourished by federal or state or local 
agencies, or private parties. Inlets may be dredged for 
navigation, beach spoil, or both goals. Approach 
channels and the Intracoastal Waterway are managed with 
minimal local role. Impacts of these combined, inter¬ 
related activities are significant and tools developed to 
manage these impacts would be nationally useful. The 
opportunity to address these problems may be unique to 
the bay area, if they are not identified as important 

resource management issues in other priority estuaries 

named in the Water Quality Act of 1987. 

3. Habitat creation and restoration. A number of specific 

problems concern habitat. The status, restoration, and 
preservation of seagrasses is the most important habitat 
issue in the bay. The special problem of intertidal 
habitat in Sarasota Bay is the lack of suitable, 

naturally occurring sites. Impaired habitat can be 
restored, but significant habitat gains will be more 

complicated to justify, design, implement and evaluate. 

A federal involvement will be needed to develop habitat 
creation projects in urban settings where potential space 
is limited. Such projects would be nationally useful, 
however, as models for similar situations. 

4. Sea level rise (SLR). Federal involvement in this issue 
far outdistances state activity despite Florida’s special 
relation to the sea. The development of a meaningful 
assessment of SLR impacts for Sarasota Bay would help the 


199 


Table 1. continued. 


area in terms of research and contingency plans and also 
represent a national demonstration project for community- 
level participation (Figure 6). The issue is also 
relevant to turbidity, habitat, stormwater and other 
major problems. 

B. State, regional and local participation. 

These problem sets are probably amenable to solution by non-federal 

governments if coordinated in a management conference framework. 

Federal participation could enhance specific work elements through 

application of national expertise. 

1. Coordinated monitoring. This set includes problems of 

data retrieval, synthesis, and application to management 
issues, and also adjustments and additions to water 
quality and other environmental samplings in the bay. A 
relevant model may be the SWIM 4 data compilation project 
underway in Tampa Bay. 

2. Shellfish sanitation. Conditionally approved areas are 
closed on intermittent or continuing bases. Harvests in 
other areas are prohibited due to runoff, or prohibited 
by default because the area has not been evaluated. A 
program to reopen, open, and study these areas is needed. 

3. Fisheries assessment, management and restoration. This 
problem set addresses the unknown status of shellfish and 
finfish stocks; recreational effort; local laws; 
allocation disputes; and habitat needs. Protection of 
stone crabs and bait shrimp, and restoration of scallops 
deserve special effort. 

4. Access improvements. Taken collectively, problems of 
scenic, beach, boating, and passive access form a set of 
significant impediments to full use of the bay. Access 
builds a popular constituency for the bay which creates 
support for other management programs but will require 
state and regional effort to accomplish during initial 
project stages. 


^Surface Water Improvement and Management Act of 1987. 


200 




RIVER 


TAMPA BAY 


•INNA 

maria 

30UN0 


ubmerged 


SARASOTA 


little 

SARASOTA 

BAY 


Figure 6. Shorelines of Sarasota Bay sumbmerged by a 5-foot rise i 
level. 


n sea 


201 

















Table 1. continued. 


C. Regional, local and private participation 

These sets are probably amenable to solution without extensive 
commitment of federal or state resources other than their role in 
providing a management framework. As in the previous case, federal 
or state involvement would significantly enhance specific work 
elements. 

1. Coordinated planning. It does not appear that 

coordination requirements of state planning laws will be 
met for Sarasota Bay, much less their codification in 
capital improvement, land use, or other implementation 
measures. Emphasis needs to be placed on adjoining 
governments and specific consistency between regional 
plans. 

2. Plans for geographic areas of particular concern (6APC). 

This set recognizes the many site-specific management 
needs occurring around the bay, and would create a 
mechanism within the larger conference process to develop 
GAPC plans with goals, plans, studies, etc. tailored to 
each area’s particular needs. The GAPC approach is an 
approved part of coastal zone management programs at the 
state level, but has not been used widely at the regional 
or local level. 

3. Educational programs. The lack of general and specific 
educational programs is one of the most often cited 
problems regarding Sarasota Bay. Educational programs, 
public participation, and related activities are central 
to all phases of bay management but can be handled 
adequately by regional and local governments. One 
nationally significant aspect of a Sarasota Bay 
educational program would be the extensive involvement of 
tourists and seasonal residents. These persons would 
return to their northern homes with conservation 
knowledge applicable to problems in distant 
neighborhoods. 

4. Boat traffic improvements. This set addresses wake 
erosion, manatee protection, seagrass signage, multiple 
uses, bridge operation, marina practices, and related 
problems. Access and use cannot be formally restricted, 
so policies and procedures related to boating must be 
developed to accommodate a growing boater population. 


202 


Table 1. continued. 


D. Local and private participation 

With the incentive and technical support of a management conference, 
local governments and private citizens should be able to make 
significant contributions to the health of the bay in several areas. 

1. Shoreline protection and management. A uniform, rational 
and ecologically beneficial approach is needed by local 
governments and waterfront landowners to remove seawalls, 
optimize dockage, enhance native vegetation, and control 
litter. (This set refers mostly to bay shorelines but 
could be addressed in conjunction with gulf beach 
projects.) 

2. Control of exotic tree species. Encroachment of natural, 
mangrove-vegetated shorelines by Brazilian pepper and 
Australian pine, and, to a lesser extent, ornamental 
vegetation can be effectively prevented through a 
cooperative program involving local governments and 
citizens. 


203 


LITERATURE CITED 


Collins, K.M. 1988. Growth and land use around Sarasota Bay: 1860- 
1987, In: E.D. Estevez (ed.)• Proceedings, Sarasota Bay Scientific 
Information Symposium (in preparation). 

Daltry, W.E. 1988. Economy of Sarasota Bay, In: E.D. Estevez (ed.), 
Proceedings Sarasota Bay Scientific Information Symposium (in 
preparation). 

DeGrove, B.D. and J. Mandrup-Poulsen. 1984. City of Sarasota wasteload 
allocation documentation. Fla. Dept. Environ. Reg. Water Qual. Tech. 
Ser. 

Dendrou, S.A., C.I. Moore and R. Walton. 1983. Final Report, Little 
Sarasota Bay circulation study, prepared for County of Sarasota Coastal 
Zone Management Division and Environmental Services Dept, by Camp, 
Dresser & McKee. 

Edwards, R.E. 1988. Fishes and fisheries of Sarasota Bay, In: E.D. 
Estevez (ed.), Proceedings Sarasota Bay Scientific Information Symposium 
(in preparation). 

Estevez, E.D. 1987. Sarasota Bay management needs and opportunities. A 
white paper prepared on behalf of the Sarasota Bay Workshop. Mote Marine 
Laboratory Tech. Rept. 104. 

Estevez, E.D. 1988. Sarasota Bay, Florida. Identification of resource 
management problems and issues. Final Report to U.S. EPA (Region IV). 
Mote Marine Laboratory Tech. Rept. No. 117A. 

Estevez, E.D. and D.A. Bruzek. 1986. Survey of mollusks in southern 
Sarasota Bay, Florida, emphasizing edible species. Mote Marine 
Laboratory Tech. Rept. 102. 

Evans, M.W. 1988. Geological evolution of Sarasota Bay. In: E.D. 
Estevez (ed.), Proceedings Sarasota Bay Scientific Information Symposium 
(in preparation). 

Evans, M.W. and R.K. Evans. 1988. Sarasota County estuarine inventory. 
Mote Marine Laboratory Tech. Rept. No. 120. 

Flannery, M.S. 1988. Watershed and Tributaries, In: E.D. Estevez (ed.), 
Proceedings of an Estuarine Seminar on Tampa and Sarasota Bays: Issues, 
Resources, Status and Management. U.S. Dept, of Commerce, NOAA, 
Estuarine Programs Office, Washington (in preparation). 

Florida Department of Environmental Regulation. 1986. Proposed 
designation of Sarasota Bay and Lemon Bay as Outstanding Florida Waters. 
Rept. to Envir. Reg. Comm. 


204 



Fortune, B. 1985. Drogue studies in Sarasota Bay. Letter rept. to Dr. 
J. Wang of Univ. of Miami by Mote Marine Laboratory, Sarasota, FL. 

Giovannelli, R.F. 1988. Stormwater Inputs to Tampa and Sarasota Bays, 
In: E.D. Estevez (ed.), Proceedings of an Estuarine Seminar on Tampa and 
Sarasota Bays: Issues, Resources, Status and Management. U.S. Dept, of 
Commerce, NOAA, Estuarine Programs Office, Washington (in preparation). 

Goodwin, R. 1988. Tampa and Sarasota Bays Circulation, In: E.D. Estevez 
(ed.), Proceedings of an Estuarine Seminar on Tampa and Sarasota Bays: 
Issues, Resources, Status and Management. U.S. Dept, of Commerce, NOAA, 
Estuarine Programs Office, Washington (in preparation). 

Habas, E.J. and C.K. Gilbert. 1974. Economic effects of the 1971 
Florida red tide and the damage it presages for future occurrences. 
Environ. Letters 6(2):139-147. 

Haddad, K. 1988. Habitat Trends and Fisheries in Tampa and Sarasota 
Bays, In: E.D. Estevez (ed.), Proceedings of an Estuarine Seminar on 
Tampa and Sarasota Bays: Issues, Resources, Status and Management. U.S. 
Dept, of Commerce, NOAA, Estuarine Programs Office, Washington (in 
preparation). 

Harvey, J. 1982. An assessment of beach erosion and outline of 
management alternatives, Longboat Key, Florida. Final Rept. to Longboat 
Key Town Commission. 154 pp. 

Heyl, M.G. and L.K. Dixon. 1988. Water quality status and trends (1966- 
1986) in Sarasota Bay, In: E.D. Estevez (ed.), Proceedings Sarasota Bay 
Scientific Information Symposium (in preparation). 

Lewis, R.R. III. 1988a. Seagrass meadows of Sarasota Bay: a review, 
In: E.D. Estevez (ed.), Proceedings Sarasota Bay Scientific Information 
Symposium (in preparation). 

Mapes, J.L. 1983-1986. Sea Turtle Conservation Program. Mote Marine 
Lab. Tech. Repts. 74(1983), 88 (1984), 96 (1985) and 1986. 

Patton, G.W. 1987a. Studies of the West Indian manatee: Anna Maria to 
Venice, Florida. Mote Marine Laboratory Tech. Rept. 105. 

Pierce, R.H. and R.C. Brown. 1986. Naled toxicity to intertidal 
estuarine organisms. Final Rept. to Sarasota Co. Mosquito Control Off., 
Sarasota, FL. 

Sarasota County, Florida. 1984. Blue Ribbon Panel for Midnight Pass, 
Summary Rept., April 24. 6 pp. 

Sauers, S.C. 1988. Present mangement of Sarasota Bay: is there a 
method to the madness? In: E.D. Estevez (ed.), Proceedings Sarasota Bay 
Scientific Information Symposium (in preparation). 


205 


Sauers, S.C. and R. Patten. 1981. A comparison of 1948 and 1979 
seagrass bed distribution in the vicinity of Whitaker Bayou, Sarasota 
Bay, Florida. Office of Coastal Zone Management, Sarasota County, 
Sarasota, Florida, February 1981, as reviewed in Wang et al., 1985. 

Seaman, W., Jr. 1988b. Federal Programs, In: E.D. Estevez (ed.), 
Proceedings of an Estuarine Seminar on Tampa and Sarasota Bays: Issues, 
Resources, Status and Management. U.S. Dept, of Commerce, NOAA, 
Estuarine Programs Office, Washington (in preparation). 

Steidinger, K.A. and T.D. Phillips. 1988. Plankton of Sarasota Bay, In: 
E.D. Estevez (ed.), Proceedings Sarasota Bay Scientific Information 
Symposium (in preparation). 

Stevely, J.M., E.D. Estevez and J.K. Culter. 1988. Bottom dwelling 
animals of Sarasota Bay, In: E.D. Estevez (ed.), Proceedings Sarasota Bay 
Scientific Information Symposium (in preparation). 

Walton, R. 1988. Meteorology and hydrology of Sarasota Bay, In: E.D. 
Estevez (ed.), Proceedings Sarasota Bay Scientific Information Symposium 
(in preparation). 

Wells, R.S. 1988. The marine mammals of Sarasota Bay, In: E.D. Estevez 
(ed.), Proceedings Sarasota Bay Scientific Information Symposium (in 
preparation). 


206 


PERSPECTIVE ON MANAGEMENT OF 
TAMPA AND SARASOTA BAYS 


Michael J. Perry 

Southwest Florida Water Management District 
Brooksville, Florida 


INTRODUCTION 


A number of local governments and regional associations of local 
governments in Florida and other states have experienced problems similar 
to those in Tampa and Sarasota Bays arising from a lack of coordinated 
management of estuarine resources. The management experience of Tampa 
Bay is particularly relevant to both bays in terms of their natural 
systems and the pressures and demands placed on the system. Although 
similar to each other in many ways, the management histories, 
opportunities, and challenges of Tampa and Sarasota Bays are different. 


HISTORIC MANAGEMENT ATTEMPTS 


Tampa Bay 

There have been numerous attempts over the past 25 years to 
establish a committee or commission to examine the problems of Tampa Bay. 
The Florida Legislature created the Tampa Bay Conservation and 
Development Commission in 1970 in response to growing public concern 
about the environmental degradation of Tampa Bay. This Commission was 
composed entirely of local legislators and other elected officials and 
was charged with determining the public interest in Tampa Bay, and to 
determine the effects of further dredging and filling on navigation and 
fish and wildlife resources in the bay. The Tampa Bay Conservation and 
Development Commission, however, never met. 

In 1982 the first symposium on Tampa Bay was held at the 

University of South Florida. The Tampa Bay Area Scientific Information 
Symposium (BASIS) lasted four days and involved topical presentations by 
50 invited speakers. Major conclusions of the symposium were that: 1) 
Tampa Bay can and should be comprehended and managed as a single 
ecological system; 2) the bay is remarkably resistant to environmental 
challenges; 3) a clear pattern of decline is evident in some measures of 
ecological condition; and 4) the management needs of Tampa Bay are 
relatively clear and, if implemented in a comprehensive and baywide 
basis, would result in tangible improvements tc the bay and its 

usefulness to people (TBRPC 1985). 

It was further concluded that the state and federal regulatory 

agencies, local governments surrounding the Bay, and an array of 


207 





industries and user groups often carry out their respective activities 
independently. The effect of bay management by a multitude of 
overlapping and often conflicting interests and jurisdictions had 
contributed to a number of environmental and growth management problems 
in the bay area (TBRPC 1985). 

In May 1982, the Tampa Bay Regional Planning Council established 
the Tampa Bay Management Study Committee. The Committee was charged with 
the task of identifying critical bay management problems and evaluating 
potential solutions for those problems. By December 1983, the Tampa Bay 
Study Committee had identified 40 specific bay issues. Because of the 
large number and complex nature of the issues affecting Tampa Bay, 
however, the Committee did not reach a consensus regarding the approach 
to the management of the bay. 

As a result, a 15 to 20 member interim steering committee provided 
for effective representation from a wide range of Tampa Bay’s business, 
environmental, and industrial interests, as well as from the local 
regulatory agencies having jurisdiction over the bay. During its six- 
month tenure, the steering committee concentrated primarily on a 
comprehensive survey and review of all entities having management 
responsibility for Tampa Bay, with the objective of documenting all major 
jurisdictional gaps and overlaps (TBRPC 1985). 

The conclusions reached at the BASIS conference underscored the 
importance of approaching estuarine management at the ecosystem level. 
In recognition of the need for a credible and structured form within 
which to pursue a more unified management scheme, the Florida Legislature 
created the Tampa Bay Management Study Commission under a special act 
adopted in 1984. The Commission received a one year mandate to recommend 
a bay management plan and work program to address priority bay management 
issues (in conjunction with ongoing efforts by the U.S. Congress, the 
U.S. Fish and Wildlife Service, state agencies, port authorities and 
other regulatory entities) for submittal prior to the 1985 legislative 
session. 

In its final report entitled Future of Tampa Bay , the Tampa Bay 
Management and Study Commission recommended to the Florida Legislature 
the establishment of a coordinating and advisory committee as an interim 
solution to the management inconsistencies plaguing Tampa Bay. Although 
no legislative action was taken, the Tampa Bay Regional Planning Council 
(TBRPC) created the Agency on Bay Management in June 1985 as an advisory 
committee of the TBRPC. 

Sarasota Bay 


The history of resource management in Sarasota Bay has not been as 
extensive as that for Tampa Bay. The first true effort was a September 
1986 workshop organized by Mote Marine Laboratory. At the workshop 
approximately 60 officials and staff members from Sarasota and Manatee 
Counties, local scientists, and educators gathered to discuss the 
management needs of Sarasota Bay and how these needs might be met through 


208 




the state-mandated comprehensive planning process (Estevez 1988). The 
workshop participants unanimously agreed on the need for an inter-local 
bay management program in place of the management void that existed. As 
a necessary step in the development of a bay management program, the 
workshop participants endorsed the concept of an intergovernmental 
symposium on Sarasota Bay, which would serve to coalesce relevant 
scientific and demographic information about the bay and to examine 
similar management processes undertaken for other estuaries (Eckenrod 
1988). 


The Sarasota Bay Area Scientific Information Symposium (SARABASIS) 
was held in April 1987. The symposium lasted for two days and coincided 
with field trips, special exhibits, and other activities related to 
Sarasota Bay. Sessions were held on a number of topics ranging from 
geology of Sarasota Bay to the biology of marine animals in the bay. 
Other sessions involved the history, economics, public use of the bay, 
and bay management. The public was invited to provide input on goals of 
management for Sarasota Bay. Symposium sessions were aimed at a general 
audience, whereas the written record will be designed as a reference 
document of use to planners, educators, and scientists. Proceedings of 
the symposium are in preparation. The interest generated by SARABASIS 
stated clearly that a conference reviewing scientific and other 
information was a timely and valuable exercise, and that the management 
needs for Sarasota Bay have been overlooked. 


EXISTING BAY MANAGEMENT EFFORTS 


Tampa Bay 

Both historically and currently, Tampa Bay constitutes the central 
geographic feature most responsible for the shipping, industrial 
development, aesthetic and recreational values that encompass the overall 
attractiveness of the region to new residents. The management of Tampa 
Bay is fragmented among a multitude of federal, state, and regional 
regulatory agencies, as well as seventeen local governments (three 
counties and fourteen municipalities) bordering the bay. Management is 
accomplished through the uncoordinated implementation of various 
monitoring, permitting, and regulatory programs. Under the existing 
management framework, jurisdictions are often overlapping; interests are 
often conflicting; and no one agency has overview authority for the bay 
or manages it as a holistic natural resource. As a result, management of 
Tampa Bay has been both wasteful and ineffective (TBRPC 1987). 

With the creation of the Tampa Bay Management Study Commission and 
the TBRPC’s Agency on Bay Management, however, there has been an attempt 
to implement a bay management program in a unified, holistic manner. The 
45 member Agency includes membership from the following groups: 

o The Florida Senate representing the Tampa Bay region; 
o The Florida House of Representatives representing the Tampa Bay 
region; 


209 




o The Tampa Bay Regional Planning Council; 
o The Southwest Florida Water Management District; 
o The U.S. Army Corps of Engineers; 
o The National Marine Fisheries Service; 
o The Florida Department of Natural Resources; 

o The Florida Department of Environmental Regulation; 

o The Florida Department of Community Affairs; 

o The Florida Department of Transportation; 

o The Florida Marine Patrol; 

o Environmental interests in the Tampa Bay region; 
o Commercial interests in the Tampa Bay region; 

o Industrial interests in the Tampa Bay region; 

o Science and academic interests in the Tampa Bay region; 

o Recreational interests in the Tampa Bay region; 

o Hillsborough, Manatee, and Pinellas Counties representatives; 
o Tampa, Manatee and St. Petersburg Port Authorities; 
o The Cities of Tampa and St. Petersburg; 
o Two other municipalities bordering Tampa Bay, and 
o The Tampa Bay region at large. 

Sarasota Bay 

Sauers (1988) and Estevez (1988) suggest that Sarasota Bay should 
be considered as unmanaged rather than mismanaged. Major decisions which 
affect the resource value of Sarasota Bay have historically resulted in a 
decline of its once pristine quality. Decisions to fill submerged bottom 
lands for residential development, discharge wastewater, dredge the 
Intracoastal Waterway, and accelerate input of large quantities of 
stormwater runoff have been made without adequate technical information 
regarding the consequences of such actions. Future decisions, such as 
construction of a cross-bay bridge, the retrofitting of urban stormwater 
and wastewater systems, or how to cope with rising sea level also have 
the potential to be made without close ecological scrutiny (Sauers 1988). 

Formerly, development decisions in and around the bay were based 
on intuition tempered somewhat by the lessons learned through mistakes 
which wasted natural resources. Now, faced with the evidence of past 
mistakes and the realization that we can no longer move to escape such 
damage, a more formal approach to decisions concerning the development 
and natural resources is considered necessary. It is imperative to 
allocate coastal resources before the rapid pace of development 
eliminates the most desirable options and results in irretrievable and 
irreversible commitments of these resources (Sauers 1988). 

Estevez (1988) reported that natural resource management is most 
effective when the resource is viewed as a single ecological unit. 
Sarasota Bay is not managed as a system at the present time, however. 
Decisions are made on a case specific basis without the benefit of 
experience from nearby cases or an overall strategy or goal for the bay. 
No system for bay management presently exists. Consequently, Sarasota 
Bay should be considered unmanaged rather than mismanaged. 


210 



Estevez (1988) further stated that another strong argument for 
viewing Sarasota Bay as an unmanaged resource is the lack of an 
institutional advocacy. There is no office or person at any level of 
government presently charged with planning for the whole bay and 
representing that view as local decisions are made. It is one thing to 
have a baywide outlook or plan; it is quite another to have a system in 
place which provides for the routine consideration of the plan and a 
speaker for the bay (Estevez 1988). 

Eckenrod (1988) reported that, in addition to reviewing the 
accomplishments of the Tampa Bay management effort, it is of value to 
managers of other coastal resources such as Sarasota Bay to examine what 
factors may have kept the Tampa Bay management effort from being more 
successful than it has been. He further suggested that factors which 
have impeded the progress of the management effort include: 1) the need 
for cohesiveness and greater simplicity; 2) the lack of full-time staff; 
and 3) limited involvement of the private sector. 


IS THERE A FUTURE FOR BAY MANAGEMENT? 


It is an interesting paradox that, although all of the interest 
groups of both Tampa and Sarasota Bay desire an effective management 
program, none truly exists. The Tampa Bay community has had the longest 
history of bay management exercises and still is unable to demonstrate an 
effective management scheme. The Tampa Bay Management Study Commission 
suggested that a Bay Management Authority would be the best mechanism. 
Although politically unpalatable at this time, it remains an option. 

The Agency on Bay Management is close to actually being a 
management program. To date, the Agency on Bay Management has served as 
a useful forum for discussion of information related to bay management 
issues. The Agency has been very successful in facilitating 
communication between responsible agencies and affected interests; 
providing coordinated recommendations regarding environmentally sensitive 
projects within the Tampa Bay watershed; establishing a vital link 
between Tampa Bay interests and the state legislature; and implementing 
the recommendations set forth in the Future of Tampa Bay . 

However, the Agency is comprised of volunteer members and has no 
regulatory authority and no delegated responsibilities for the management 
of Tampa Bay as a single, holistic system. The Agency is also stymied by 
severely limited funding, and is staffed by TBRPC employees on a part- 
time basis. Due to these constraints, the Agency is therefore not the 
final answer for bay management needs of Tampa Bay at this time. 

During the 1987 legislative session, the Florida Legislature 
passed the Surface Water Improvement and Management (SWIM) Act, the 
intent of which was to initiate the restoration and protection of surface 
water bodies on a statewide basis. The legislation mandated that the 
State’s five Water Management Districts implement the program. The State 


211 




also created the SWIM Trust Fund to which appropriations would be made to 
support the program. The first year’s appropriation of $15 million was 
allocated for six priority water bodies, four of which were estuarine 
waters (including Tampa Bay). The Southwest Florida Water Management 
District has, therefore, been thrust into the bay management picture by 
the legislation. 

The District has all or part of 16 counties and approximately 
10,000 square miles within its jurisdiction, which includes the southwest 
coast of Florida. In recent years, the District has expanded its 
traditional role of helping to resolve flooding problems. It now 
performs regulatory functions for well construction, consumptive use, 
surface and stormwater management, and aquatic plant management. Surface 
water and stormwater discharge permitting acts to regulate the impact of 
new construction on water quantity, water quality, wetlands or other 
natural resources. The District historically has had little involvement 
in estuarine areas; however, it now has been given the responsibility for 
improving Tampa Bay. 

The legislation instructs the District to designate priority water 
bodies, and to prepare and implement restoration and management plans for 
these water bodies. Although Tampa Bay has been identified in the 
legislation, it is not inconceivable that the District may become 
involved with many other estuarine areas (such as Sarasota Bay) within 
its jurisdiction. It also is not inconceivable that the water management 
district may be the appropriate mechanism for effective bay management, 
since the District now: 

1. has a State mandate to become an active participant in bay 
management; 

2. already has regulatory responsibilities for surface water 
permitting and may soon be delegated additional permitting 
responsibilities; 

3. has taxing authority and can generate the revenue. 

Sarasota Bay has not had the checkered history of management 
attempts and, consequently, does not have the background information that 
typically would be generated through the management development process. 
This is not to say that nothing is known about the bay; in fact, much is, 
but this knowledge has not been used to develop a comprehension of the 
bay as an ecosystem. Without information of this type, the corrective or 
restorative functions of a management system cannot operate. 

Estevez (1988) noted that goals must exist for a resource 
management system to operate. Such goals should be defined for and by 
the public and be practical, verifiable, and meaningful. Practical means 
achievable with existing technical skills, rather than political or legal 
feasibility. Verifiable means that improvements occur as a result of 
management which the lay public can perceive through everyday use of the 


212 


bay. Meaningfulness if defined relative to improvement of the bay 
compared to its previous condition. 

Goals for Sarasota Bay as a whole do not exist now, except insofar 
as regional plans contain general language applicable to all of the 
region’s bays. However, Sarasota Bay is unique by its division into two 
regional planning areas, so even the existing regional plans agree only 
by coincidence where the bay is concerned (Estevez 1988). 

The hope for a management program for Sarasota Bay should not be 
abandoned. In 1986, the 99th Congress passed a reauthorization of the 
Water Quality Act, which drew an executive veto after the session closed. 
In 1987, the 100th Congress overrode a second veto to authorize the Act 
as originally drafted. An element of the Act (Section 320, National 
Estuary Program) identifies nationally significant estuaries threatened 
by pollution, development of overuse; promotes comprehensive planning for 
these estuaries; encourages the preparation of management plans; and 
enhances the coordination of estuarine research. 

Governors may nominate estuaries of national significance to the 
Administrator of the Environmental Protection Agency and request a 
management conference to develop a comprehensive management plan for the 
estuary. It is important to note that the federal program is called a 
management conference, but in fact involves much more than a conference 
per se. Special panels are convened as part of the process to set 
policy, interpret data, collect new information and produce educational 
programs. The conference should not be confused with the Bay Symposium 
described earlier in this paper. 

The act intends that the Administrator give priority consideration 
to several estuaries across the nation, including Sarasota Bay. The 
principal purposes of the management conference are to collect existing 
data and assess trends in water quality, natural resources and uses of 
the ecosystem; develop relationships between point and non-point loadings 
of pollutants to water quality and natural resources; and develop, 
implement and monitor a comprehensive plan that identifies priority 
corrective actions. 

Participants in the management conference are specified and 
include federal and state governments, public and private educational 
institutions and the general public. The conference has up to five years 
to develop a plan which then can be implemented with state and federal 
grants. 


SUMMARY AND CONCLUSIONS 


The experience of other bay management programs supports the view 
that the extra effort expended to develop a bay management plan is offset 
by the extra benefits which result. The management objectives for Tampa 
Bay and Sarasota Bay are quite similar, however, the systems are 
inherently different. That fact notwithstanding, both bays must be 


213 



comprehended and managed in a holistic manner. The involvement of a 
myriad of agencies at all levels of government speaks to the need for 
consolidation, with few agencies, preferably one, having comprehensive 
jurisdiction. Anticipated solutions must be implemented with direct 
planned actions and not operate under a crisis-management approach. 
Currently, decision-making is the responsibility of many disparate 
groups. These groups must communicate and interact with each other to 
promote a proactive rather than reactive approach. 


214 


LITERATURE CITED 


Eckenrod, R.E. 1988. Management of Tampa Bay: the process and its 
lessons, In: E.D. Estevez (ed.), Proceedings, Sarasota Bay Area 
Scientific Information Symposium (SARABASIS). In press. 

Estevez, E.D. 1988. Sarasota Bay Management Needs and Opportunities - a 
White Paper. Mote Marine Laboratory Tech. Rept. No. 104. February 1987. 

Sauers, S. 1988. Present management of Sarasota Bay, method or madness? 
In: E.D. Estevez (ed.). Proceedings Sarasota Bay Area Scientific 
Information Symposium (SARABASIS). In Press. 

TBRPC. 1985. Future of Tampa Bay. Tampa Bay Regional Planning Council. 
St. Petersburg, FL. June. 

TBRPC. 1987. State of Tampa Bay. Tampa Bay Regional Planning Council. 
St. Petersburg, FL. June. 


215 


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